383 vs 377 [Archive] - Chevy Nova Forum

: 383 vs 377


69NovaSS
27th-December-2008, 10:47 AM
SO lets hear your thoughts on this.

The old adage that there is no substiton for cubes is likely a moot point here as there is only a 6 cube difference. Thats like saying a 355 will ALWAYS beat a 350 due to the extra cubes:rolleyes:

So lets look at what we have. With the 383 we have a 350 block with a 400 stroke. With the 377 you have a 400 block with the 350 stroke. BUT you also have less valve shrouding with the 377 due to the larger bore size when compared to the 383. Does the shorter stoke of the 377 lend its self to high RPM use like many would say? Has the 377 taken on the mythical rpm number of the ol' 302 SBC? We've all heard storys of 10,000 RPM 302's.

So which do you think would have the upper had between two equally prepared motors. Would the 383 or the 377 come out on top?

BTW would one engine have better longevity then the other? I would think for any given RPM the piston speed of the 377 should be less than the 383. Would this not lend itself to motor longevity?

Mike Goble
27th-December-2008, 10:57 AM
Equally prepared or identically prepared?

Why would you run them at the same rpm?

69NovaSS
27th-December-2008, 11:05 AM
Equally prepared or identically prepared?

Why would you run them at the same rpm?


hmmm...that is a good question...as equally prepared and identically prepared are two differnt things..identically prepared motors I suspect would leave one of the motors at a disadvantge so why not go with equally prepared?

As far as rpm is concerned even at street rpms (ie 2000-3000 rpm) there would be a difference in piston speed betwen these two motors due to the difference in stroke length.


I'm just hopping to get some good disscussion going and to maybe give me something to think about:)

Mike Goble
27th-December-2008, 11:11 AM
Why not just run them at equal piston speeds instead of focusing on the rpm? What is the difference in piston speed between the two engines?

69NovaSS
27th-December-2008, 11:17 AM
Why not just run them at equal piston speeds instead of focusing on the rpm?

well the rpm really isnt important I was just pointing out that at any rpm be it idle or max rpm or anywhere inbetween the piston speed for the 377 will be lower then that of the 383. I was just thinking it might be a longevity factor we could consider in our disscussion.

Chev made a lot of 400's and 350's that lasted a long time so possibly the piston speed isnt that big a factor:confused:

But to get these two motors to have the same piston speed you will have to run the 383 at lower rpms then the 377. Is that what you ment by equally prepared?

69NovaSS
27th-December-2008, 11:26 AM
What is the difference in piston speed between the two engines?

I believe at 5000rpm the 377's piston speed is 2905.8 ft/min while the 383's piston speed is 3131.25 ft/min.

I hope I did the math correctly:o

Not really a hugh difference but over the life of a motor it must add up:confused:

bowtie0069
27th-December-2008, 12:59 PM
Well, I'm building a 377 with a 350 block so now there is another variable!
Standard 4" bore/3.75 stroke is also a 377" Your combos are based on .030" over bores. If I ever get this thing finished, I'll let you know how it turns out!

veno
27th-December-2008, 02:46 PM
6ci will make a difference... say you making 1.2hp per cube....

383X1.2=459.6

377X1.2=452.4

a difference of 7.2hp.... that's a lot when winning counts...

or 1.5hp per ci...

383x1.5=574.5hp
377x1.5=565.5

that a difference of 9hp

don't for get the difference in Torque

69NovaSS
27th-December-2008, 03:05 PM
don't for get the difference in Torque

based on the old rule of thumb the longer stroke motor should make the most torque. SO that would give the 383 the thumbs up in this case.:)

veno
27th-December-2008, 03:12 PM
just a dumb Q here... if you access to a 400 block and are looking to make the best of it.. a 406 would be 29CI larger than the 377:eek: and have unshrouding you eluded to....

and 29CI x 1.2hp=34.8hp that a car at the finish line..

69NovaSS
27th-December-2008, 03:19 PM
just a dumb Q here... if you access to a 400 block and are looking to make the best of it.. a 406 would be 29CI larger than the 377:eek: and have unshrouding you eluded to....

and 29CI x 1.2hp=34.8hp that a car at the finish line..


Absolutely, I agree 100%. If I only had a 350 block I would personally build a 383 or larger(depending on crank I used) and with a 400 the smallest it would be is a 406(again depending on crank used). I'm just wondering out loud her if there would be much of a difference between a 377 or a 383. Honestly to me, destroking doesnt make a lot of sense to me. Cubes are cheap power but for others however the 377 seems to have the mystic that the 302 has. You know it can rev to 10K and eats BBC's for breakfast...at the moment I have access to nothing so this is all academic.:o

levisnteeshirt
27th-December-2008, 04:50 PM
the mass of the rotating parts is going to be lighter with the 377, it should accelerate faster , and load on the bearings should be less. Rod length is not going to be as critical with the 377 as there is more room to increase length with the 377. A 377 is not as expensive to build when you switch over to forged internals , NAPA used to sell a 350S crank ( forged ) for 200 bucks .010/.010. I haven't checked in a while if that is still available but it used to be. A few extra extra cubes can be had with the 377 by offset grinding the crank to small journal bringing the stroke to 3.562 which you now have a 386. A bigger engine with high RPM potential. You can shave .040 off of the crown of a 377 piston ( which using a 5.7 350 rod , its a reg 400 piston that used the 5.565 rods ) and do this , or 386 pistons can be ordered. The biggest drawback of the 377 goes back to the 400 block , which love it or hate it , it is what it is.

veno
27th-December-2008, 05:45 PM
the mass of the rotating parts is going to be lighter with the 377, it should accelerate faster , and load on the bearings should be less. Rod length is not going to be as critical with the 377 as there is more room to increase length with the 377. A 377 is not as expensive to build when you switch over to forged internals , NAPA used to sell a 350S crank ( forged ) for 200 bucks .010/.010. I haven't checked in a while if that is still available but it used to be. A few extra extra cubes can be had with the 377 by offset grinding the crank to small journal bringing the stroke to 3.562 which you now have a 386. A bigger engine with high RPM potential. You can shave .040 off of the crown of a 377 piston ( which using a 5.7 350 rod , its a reg 400 piston that used the 5.565 rods ) and do this , or 386 pistons can be ordered. The biggest drawback of the 377 goes back to the 400 block , which love it or hate it , it is what it is.

If you say so..:rolleyes:

64PRONOVA
27th-December-2008, 06:34 PM
I built my first 377 back in the late 70s when not too many people were building them other than dirt track racers. In the late 70s, I was on a pit crew when the cubic inch limit for winged super sprint cars was increased from 355 to 378 cubic inches. Overnight, the 377 became the engine of choice.

My first 377 used a 400 2-bolt block with a forged 350 crank utilizing the bearing spacers, stock rods and forged flat-tops. I ran a set of 461 heads on it with the Duntov 69 z/28 30/30 "off road special" solid-lifter camshaft.

It was a quick engine and definitely sounded radical. A good 4-speed set-up.

I ran it for about 3 years and used to do pretty-well against the other small blocks and even a lot of the milder big blocks. That was until my buddy dropped a new 383 in his Camaro. He used to eat me up with it.

I built two more 377s during the 80s for my 64 Nova but got tired of losing to 383s and 406s so finally upgraded to a 406 and never built another 377.

The 377 is a good engine though, but don't expect miracles from it. It's basically a big 350, a 350 bored-out 1/8" and performs similar to and has the same personality as a very strong 350.

It should be noted that the second they raised the cubic inch limit from 378 to 410 cubic inches for the winged super sprint cars, the 377 ceased to exist in the sport. They simply could not compete against the 406s that replaced them.

levisnteeshirt
27th-December-2008, 07:11 PM
on how each perform , is going to be how you exploit the potential of each one. IMO the 377, is going to need more converter stall and higher RPM range selected parts to out perform or be equal to a 383 thats had its internals and drive train maximized for its benefits of increased low RPM output.

I've out ran a few 383's with a 355. But its all in whats been done to them and the whole package.

veno
27th-December-2008, 08:26 PM
jack the giant killer? you can take a 287 286 ci 12,000 rpm super comp engine and hit the 8's if thats your intent... I would rather try to keep the rpm down and CI up...:D

69NovaSS
28th-December-2008, 08:14 AM
jack the giant killer? you can take a 287 286 ci 12,000 rpm super comp engine and hit the 8's if thats your intent... I would rather try to keep the rpm down and CI up...:D

that is sort of what I was refering to with the 377 taking on almost mythical rpm capabilites sort of like the 302 has.

69NovaSS
28th-December-2008, 08:15 AM
Well, I'm building a 377 with a 350 block so now there is another variable!
Standard 4" bore/3.75 stroke is also a 377" Your combos are based on .030" over bores. If I ever get this thing finished, I'll let you know how it turns out!

I'd be interested in hearing how this works out. Is this a new block or are you freshing up on with new rings?:)

veno
28th-December-2008, 10:53 AM
the 350 block 377 is nothing but a stock bore 350 with a 3.75 stroke.... bore it .030 and its a 383... no magic or mythical conundrum there....

While it is just a blast to build and spin a engine to 9k and above.... it wreaks havoc on the valve train and harmonics shorten the rotating life something fierce.... A High RPM engine requires the utmost care and maintenance... valve springs will be the expensive and require replacing often, bottom end will need to be checked, valve life as well as seats will be hammered hard... rod life will do way down.....

if you want to build a 377 .. and spin it to the moon I suggest a American made ultralite crank, like Crower, Winberg, or Lunati... a dart block... a very good set of aluminum rods GRB comes to mind or titanium rods, either CP, wiseco, aries ultralite gas ported pistons.
hollow stem SS or titanium valves, titanium retainers, the best rocker arms, smith bro's. push rods... a very nasty solid roller cam.... and the best rollers...

contact Perfect circle for a suggestion on ring package ans spacing and be prepared to spend 200.00 for a set of rings...

around 2k in machine work....


when you build a high rpm engine the cost goes way up... you think it costs a lot to build? wait till you have to replace it...

bowtie0069
28th-December-2008, 01:29 PM
The one I'm building is a late model roller block, Probe pistons(343g), 6" I-beam rods, lightweight 4340 crank, and not too sure as to the rest of it yet. It will have a 7000 rpm max.

Ryan65
28th-December-2008, 02:07 PM
You need to know what the intended use of these engines are before you can compare them.Always build the most cubes for a street driven car,this will allow less rear gear and lower stall speeds to be used increasing engine life..

Pwrtrip75
28th-December-2008, 02:27 PM
I got a 377 shortblock from a guy who ran it 9000rpms.

I put it in my Nova with a decent solid roller and some brownfeild heads.

My friends Malibu with a 406 had dart 215s, same cam, I had a Team G intake, he had a vic jr, I had a 4800 stall, think he had a 4000, I had 3.50 gears 29" tall tire, he had 3.73 gears 28" tires, my car was a couple hundred lbs heavier. Same compression. The heads flowed like almost identical.

Anyway very similar setups.... My car was a monster compared to his. i'd always slowly pull on him and beat him by about a 1/2 second.

Could be just that I had it tuned in better also.. :cool:

They probably arnt much different except if one would want a high rpm endurance engine, the 377 might be a better option...depending on parts you use.

stock z/28
28th-December-2008, 02:45 PM
I think I would rather have the 4.155 bore version.

veno
28th-December-2008, 02:53 PM
Hi Jeff..

I agree 4.155

I think 4.200 would be even better...:devil:

Jeff... who makes the 1 piece spacer bearings? or should I say the thick bearing?

and whats your take on the spacers verses the one piece bearing?

6NOVA4
28th-December-2008, 04:29 PM
I think you can get the bearing spacers from clevite or FM.

IMO for street cars, you can't beat the extra torque the 383 is gonna produce at lower RPM's vs a 377. Broader torque curve. Big bore/short stroke engines tends to make less torque but make up in upper RPM hp. A short RPM range too. That's why you need lower gears and a higher stall converter. All out drag car weighing 3,000# or less with 377 and 4.56's and converter and good hooking suspension that combo should rocket out of the gate and 60ft' excellent and make some bitchin Hp on the big end, screamin at 7800!!!
A heavy drag car with matched converter and say 4.11's with good hooking suspension may not(and that's a big if)60ft as good but will be a monster from 60ft to the 660ft mark with the extra tq pulling the car down the track, making excellent power to 7,000RPM's

Ask John(camgrinder) he has a 377 in his 71 nova on spray runs 10.14@136 on 9" slicks

bowtie0069
28th-December-2008, 07:38 PM
I prefer the bigger bore for making power, but the small bore 377 I'm doing isn't strictly to make power--I'm trying make decent power, along with good mileage, so it's going to be a lot different from my usual stuff--short duration/lots of lift/hydraulic roller/light rotating assembly/slick coatings on bearings and other areas, the pistons have 1.2/1.3/3.0 mm low drag rings, I might run the vacuum pump on this one for testing, but not sure yet--cylinder head choice is still to be determined, but some beehive springs will be in there, along with some titanium pieces, and stupid high ratio rockers.

levisnteeshirt
28th-December-2008, 08:02 PM
I got a 377 shortblock from a guy who ran it 9000rpms.

I put it in my Nova with a decent solid roller and some brownfeild heads.

My friends Malibu with a 406 had dart 215s, same cam, I had a Team G intake, he had a vic jr, I had a 4800 stall, think he had a 4000, I had 3.50 gears 29" tall tire, he had 3.73 gears 28" tires, my car was a couple hundred lbs heavier. Same compression. The heads flowed like almost identical.

Anyway very similar setups.... My car was a monster compared to his. i'd always slowly pull on him and beat him by about a 1/2 second.

Could be just that I had it tuned in better also.. :cool:

They probably arnt much different except if one would want a high rpm endurance engine, the 377 might be a better option...depending on parts you use.


what carb and if you had his car , what would you change ??

6NOVA4
29th-December-2008, 12:30 AM
your nova weighs more than a malibu? hmmm... sounds like the combo runs good. why would you want to change it? as for carbs, what was on it?

Pwrtrip75
29th-December-2008, 12:53 AM
your nova weighs more than a malibu? hmmm... sounds like the combo runs good. why would you want to change it? as for carbs, what was on it?


I dont remember what he had 8xx holley I think, I had a 950HP, yea my car weighs 3460 w/o me in it. This was like 5-6 years ago.

Why does everyone think you want TQ over HP for a street car? Its the exact opposite. On the street you dont have superb traction, so a HP engine is the way to go. Unless you run slicks and VHT the road, all a ton of low end TQ is going to do it kill you. I guess it depends on if your talking practicality or the look at me factor. A TQ engine is good at the track cause you can unleash it all off the line and hook.

6NOVA4
29th-December-2008, 01:30 AM
its all relative. It's also about the overall combo. Torque is what gets the mass moving. HP is what keeps it accelerating as torque drops off. HP is a function of torque. Yes an engine that makes alot of torque can and will blow the tires off. You got to have the suspension/tires to control it.

Its hard to say why your 377 beat your buddy's 406. comparing apples and oranges I guess. what were the ET an MPH numbers?

6NOVA4
29th-December-2008, 01:41 AM
I remember a similar deal with a couple of buddies of mine. Back in the day my buddy dave had a 71 chevelle and we build a 383 flattop pistons, ported 76 cc stock heads, comp 480/280 hydraulic cam, dual plane intake, roller rockers, 750 vac sec carb, th350 with 2500 stall converter, 3.73's, 1 5/8" headers, 2 1/2" exhaust. Car ran good. My other buddy Mike had a 68 camaro with a 350, stock bottom end with ported 64 cc heads, crower hydraulic 480/280 cam, torker intake, 650 dp, th 400, 2500 stall, 3.73's, 1 5/8" headers, 2 1/2" exhaust.

Guess who beat who? Mike's camaro on the big end would edge dave out by a fender. They would always punch off from 3,000 RPM in 1st gear. Apples and oranges. My 355 in my nova would WALK all over them. Of course their cars were more "street" cars than mine. :yes:

64PRONOVA
29th-December-2008, 04:15 AM
Not in my experience. My buddy with the 383 even had a heavier car than my 64 Nova and could still beat my 377 with his 383. No pipe dreams. Equally-prepped and very comparable engines running about the same compression ratio and everything. The stroker beat the puched-out 350 every time. A 377 isn't a whole lot more than a 355 really. Not like the 383s seem to be. Torque is where it's at. You can really feel it in the seat of your pants. Then when I upgraded to a 406, I beat him every time.

My 377 used to blow away the 302 z/28s though.

levisnteeshirt
29th-December-2008, 01:20 PM
a good 406 is really tough to beat.

I guess i was around too many 355's that would go to 8000 and make your head feel like it was going to get pushed through the head rest watching the tach sweep by 7500 and not slowing down to be interested in engines that make low end torque.

Ya can't get weak knee'd in your parts selection when you build something thats going to wind instead of pull down low or the low-end bruisers will get you. Gear selection begins at 456 and up , 513 and up if you really want it to work good. Had a friend back in the day that drove a 70SS -355 Nova to school with a 6.14 gear and a 4 SPEED, it was insanely quick. Another one with a 355 4 spped /513 gear ( huge hydraulic Lunati cam 320/500 lift that changed the way you'll think about hydraulic cams ). The big block fellas in the parking lot didn't mess with these guys much ,,lol. I'm sure the 1/4 would have been a different story but they had a hard time getting a race in the 1/8 once the word got out what they had.

Pwrtrip75
29th-December-2008, 02:12 PM
get a decent converter and you wont need 6.14 gears.

6NOVA4
29th-December-2008, 11:07 PM
SO lets hear your thoughts on this.

The old adage that there is no substiton for cubes is likely a moot point here as there is only a 6 cube difference. Thats like saying a 355 will ALWAYS beat a 350 due to the extra cubes:rolleyes:

So lets look at what we have. With the 383 we have a 350 block with a 400 stroke. With the 377 you have a 400 block with the 350 stroke. BUT you also have less valve shrouding with the 377 due to the larger bore size when compared to the 383. Does the shorter stoke of the 377 lend its self to high RPM use like many would say? Has the 377 taken on the mythical rpm number of the ol' 302 SBC? We've all heard storys of 10,000 RPM 302's.

So which do you think would have the upper had between two equally prepared motors. Would the 383 or the 377 come out on top?

BTW would one engine have better longevity then the other? I would think for any given RPM the piston speed of the 377 should be less than the 383. Would this not lend itself to motor longevity?

lol... we got strayed from the original question.

383: torque of a 400 but not the overheating problems(old school thinking) cheap and easy to build, over 400 ft/lbs tq from 2500 up.

377: can rev it up past 7500, makes excellent power, helps overcome overpowering small tire cars due to the lack of tq vs a 383 cheap and easy to build.

302: created to meet SCCA ci requirements. NO torque but you can rev that sucker to 8500+

Both the 377 and 383 engines IMO are good and will last a long time. It all depends on how the engines are abused and what parts are used. Better rod/stroke ratio w/ 377 less side loading.

Either one will get the job done, you just gotta set it all up to get the best out of it.

For a primarily street driven car? IMO I'd pick a 383 over a 377, just want that torque to get the car moving, don't need to run steep gears and a big stall converter.

Who has the upper hand? nobody really. Just my .02

Mike Goble
29th-December-2008, 11:16 PM
lol... we got strayed from the original question.

383: torque of a 400 but not the overheating problems(old school thinking) cheap and easy to build, over 400 ft/lbs tq from 2500 up.

377: can rev it up past 7500, makes excellent power, helps overcome overpowering small tire cars due to the lack of tq vs a 383 cheap and easy to build.

Both the 377 and 383 engines IMO are good and will last a long time. It all depends on how the engines are abused and what parts are used. Better rod/stroke ratio w/ 377 less side loading.



How much torque difference is there between the 377 and 383 configurations? Do you actually think that a 383 will produce the torque of a 406? How do you get side loading and what affect does it have on the engine?

How about a 383 with a 4.25" bore and a 3.375" stroke with a 6.35" rod? I'll bet that engine is famous as a high rpm screamer and all around powerhouse.

veno
29th-December-2008, 11:53 PM
How about a 383 with a 4.25" bore and a 3.375" stroke with a 6.35" rod?


yeah, but the heads will hold it back!:mad:

Mike Goble
29th-December-2008, 11:55 PM
How about a set of Max Wedge heads?

veno
30th-December-2008, 12:00 AM
I think I would lean to the 906 castings, or the b1

6NOVA4
30th-December-2008, 12:13 AM
How much torque difference is there between the 377 and 383 configurations? Do you actually think that a 383 will produce the torque of a 406? How do you get side loading and what affect does it have on the engine?

How about a 383 with a 4.25" bore and a 3.375" stroke with a 6.35" rod? I'll bet that engine is famous as a high rpm screamer and all around powerhouse.

I'm sure some of you guys have those "desktop dynos" you can plug in the numbers and figure it out for yourselves. My statement of the "torque of a 400" is what they used to say back in the day when the 383's were becoming popular. NO I don't think a 383 will produce the same torque, that's obvious. BUT it will make a fair amount. I've done a couple of dyno sims and it seems IMO the 377 torque curve was very peaky wasn't as broad as the 383. At the machine shop were I work part time we haven't built any 377's since we got the dyno so we can't compare notes. On the 383's and 406's we've done we've made over 500hp respectively on each engine, I'll go back and see what the tq figures are and compare.

How do I get side loading? Hmmm let's see. Well when I took my 355 apart and saw how nice the skirts looked liked they never been run. Then after I built my 406 and went to freshen it I noticed how much wear there was on the skirts. The angle in which the piston is at on a 350 vs a 400 is obvious, hence more load on the skirts. The crank arm on a 400 is farther away from center than a 350 thus provides more leverage. A 383 with a 4.250 bore and 3.375 stroke with 6.350 rods? Hmmm well that sounds like an expensive small block. I had an idea to build a 427 small block with a 4.250 bore and a 3.75 stroke like a BBC and Brodix 12x12 heads and and a sheet metal tunnel ram with split doms...how'd that be?

6NOVA4
30th-December-2008, 12:15 AM
wait so are you talking chrysler engines? Hmm I was talking chevys.

I could care less about a 383 chrysler...lol

veno
30th-December-2008, 12:25 AM
wait so are you talking chrysler engines? Hmm I was talking chevys.

I could care less about a 383 chrysler...lol

a engine doesn't know what is printed on its valve cover..

you could do the same with a 4.25 bore BBC...

6NOVA4
30th-December-2008, 12:55 AM
a engine doesn't know what is printed on its valve cover..

you could do the same with a 4.25 bore BBC...

very true. But I thought we were talkin about sbc's did I miss the sarcasm...lol...?

283nova
30th-December-2008, 01:23 AM
unless your racing heads up racing, anything can be competiave, i run my 301, when i won this year and in 06 i had THEE smallest motor in my class. bbc's sbc's sbf's bbf's bbm sbm, little bit of everything. mopar chevy ford. but like i said unless its heads up either of those motor will be competiave either your car will run a number or it wont.. my budy had a 69 nova 377 t-ram he ran 9's on the juice 10 without no big deal? his dads car is the mystery car, 70 camaro with a 233 cube SBC runs 10.80's:eek: some custom destroker deal.

veno
30th-December-2008, 01:35 AM
very true. But I thought we were talkin about sbc's did I miss the sarcasm...lol...?

funny..... thing is assumptions make us lock our selves in boxes...... he never said any thing about brand or block size!:devil:

wasnt it Allen Shepard driving for rhear-morrison in like 73 that ran a destroked bbc in prostock and cleaned every body's clock who was stuck in the SBC ranks? paid the weight penalty for the BBC yet had to run the same displacement?

Mike Goble
30th-December-2008, 07:17 AM
How do I get side loading? Hmmm let's see. Well when I took my 355 apart and saw how nice the skirts looked liked they never been run. Then after I built my 406 and went to freshen it I noticed how much wear there was on the skirts. The angle in which the piston is at on a 350 vs a 400 is obvious, hence more load on the skirts. The crank arm on a 400 is farther away from center than a 350 thus provides more leverage. A 383 with a 4.250 bore and 3.375 stroke with 6.350 rods? Hmmm well that sounds like an expensive small block. I had an idea to build a 427 small block with a 4.250 bore and a 3.75 stroke like a BBC and Brodix 12x12 heads and and a sheet metal tunnel ram with split doms...how'd that be?

How much more side loading of the piston is there between your 355 and your 406? Assume the same cylinder pressure and crank angle.
Would you equate more leverage on the crank to more torque? Newton has to be satisfied inside an engine, also, so you can't push in just one direction.

I had one of those exotic big bore, short stroke, long rod 383's in a 68 Plymouth I bought new in 1968. It came stock with shaft rockers for better valve control and a front mounted distributor to reduce spark scatter, it was quite a high performance piece...

6NOVA4
30th-December-2008, 05:29 PM
funny..... thing is assumptions make us lock our selves in boxes...... he never said any thing about brand or block size!:devil:

wasnt it Allen Shepard driving for rhear-morrison in like 73 that ran a destroked bbc in prostock and cleaned every body's clock who was stuck in the SBC ranks? paid the weight penalty for the BBC yet had to run the same displacement?

you're right. I assumed the thread was about 377 vs 383 in terms of a small block chevy. I didn't know other brands were swapping 400 cranks in 350 blocks and vise versa. My bad:bored:

It was Lee Shepard who drove for David Reher and Buddy Morrison. I found these articles for you.

http://www.nhra.com/50th/top50/L_Shepherd12.html

http://www.competitionplus.com/08_19_2004/lee_shepherd.html

Hope this helps...:D

6NOVA4
30th-December-2008, 05:38 PM
MIke I don't know what your getting at, a bash on me of some sort or what. I answered your question, you're a smart guy I figured you knew what I'm talking about. I don't know if I can "measure" the amount of side loading, I just know from what I seen and from what my teachers and mentors have told me. Sorry if that's not good enough for you. It is what it is.

Like I said to veno I thought this thread was about 377 vs 383 sbc's. I didn't know the thread included the infamous 383 chrysler, the little big block that could.

Seems I'm outnumbered here so I will respectfully bow out of this thread.
Again these were MY opinions.:cool:

ddoyel
30th-December-2008, 06:20 PM
The 377 combo in my little AC replica works great. With only 2450 lbs and street driven it is less likley to spin the tires unless wanting to. at 425 ftlbs to its 505 hp works pretty good. I never understood how those original 427 cobras could get anywhere trying to get traction. I would hate to try to carve some of the canyons ive driven with more torque not to mention the supposed faster reving of the 377. With a jag rear and no traction devices 1.53 60' on drag radials was possible. But i would say the heavier the car there really is no substitute for cubic inches.

veno
30th-December-2008, 06:49 PM
how about a 4.3 bore and 3.3 stroke mel? bet that thing could breath and scream

stock z/28
30th-December-2008, 08:56 PM
How much more side loading of the piston is there between your 355 and your 406? Assume the same cylinder pressure and crank angle.
Would you equate more leverage on the crank to more torque? Newton has to be satisfied inside an engine, also, so you can't push in just one direction.

I had one of those exotic big bore, short stroke, long rod 383's in a 68 Plymouth I bought new in 1968. It came stock with shaft rockers for better valve control and a front mounted distributor to reduce spark scatter, it was quite a high performance piece...

Mike,

Did that 383 have the trick light weight wrist pins? Around 12 lbs a piece?:)

I think the pistons were real light as well.

I remember the shaft system as well. I think it used a an Allen head adjustment screw? Oh I remember now they were not adjustable were they?


I think the front mounted dist was pretty cool as well. It increased max RPMs to what? (with the trick 12 lb pins, the stock pins were probably a bit heavy for high rpms?)


I do love the sound of the Mopar starters though.


Thanks Mike

Jeff

veno
30th-December-2008, 09:18 PM
It was Lee Shepard who drove for David Reher and Buddy Morrison. I found these articles for you.

http://www.nhra.com/50th/top50/L_Shepherd12.html

http://www.competitionplus.com/08_19_2004/lee_shepherd.html

Hope this helps...:D

My age is getting the best of me....Allen Shepard walked the moon and played golf up there.....

it does help.... Lee Shepard was a hela driver and shifter... bet Ronnie Sox hated him!:devil:

I remember, I and my best friend were working on his 57 when the news came over the radio..... we were both in a small state of shock.... Lee was such a fabulous driver....We both said it had to be car failure...and not driver error....

Old School
30th-December-2008, 09:45 PM
My age is getting the best of me....Allen Shepard walked the moon and played golf up there.....

it does help.... Lee Shepard was a hela driver and shifter... bet Ronnie Sox hated him!:devil:

I remember, I and my best friend were working on his 57 when the news came over the radio..... we were both in a small state of shock.... Lee was such a fabulous driver....We both said it had to be car failure...and not driver error....

Most had never heard of Ardmore, OK before Lee's crash. Now if I see or heard of Ardmore that is the first thought I have. Lee Shepherd was the best head porter/driver of that era. Sorry to get off topic.

Biggest difference I see in 377/383 is where you want your torque peak at, and it will not be as far apart as most think.

Mike Goble
31st-December-2008, 12:06 AM
Mike,

Did that 383 have the trick light weight wrist pins? Around 12 lbs a piece?:)

I think the pistons were real light as well.

I remember the shaft system as well. I think it used a an Allen head adjustment screw? Oh I remember now they were not adjustable were they?


I think the front mounted dist was pretty cool as well. It increased max RPMs to what? (with the trick 12 lb pins, the stock pins were probably a bit heavy for high rpms?)


I do love the sound of the Mopar starters though.


Thanks Mike

Jeff

You could get the Max Wedge rockers that were adjustable with the little ball on the inner end. I won my class at the 1974 AHRA Winternationals with the little Mopar, and in 1975 we won the AAI/DeVry drags at Mel Larsons. We were 8 tenths faster than any other vehicle there, and they had to take a motorcycle off the big trophy and put a car up there.

Mike Goble
31st-December-2008, 08:58 AM
MIke I don't know what your getting at, a bash on me of some sort or what. I answered your question, you're a smart guy I figured you knew what I'm talking about. I don't know if I can "measure" the amount of side loading, I just know from what I seen and from what my teachers and mentors have told me. Sorry if that's not good enough for you. It is what it is.

Like I said to veno I thought this thread was about 377 vs 383 sbc's. I didn't know the thread included the infamous 383 chrysler, the little big block that could.

Seems I'm outnumbered here so I will respectfully bow out of this thread.
Again these were MY opinions.:cool:

It's not intended as any sort of bashing, I'm merely trying to get you to think about the physics of the internal combustion engine.

I learned about rod angles and crankshafts early on in my life while riding my bicycle. I discovered that leaning back and creating a better angle on the pedal crank would put more torque to the rear wheel. Guys who didn't take advantage of the improved angle got left in the dust.

The ideal connecting rod would be no connecting rod at all. If you could design an engine with the piston connected directly to the crankshaft so the piston/crank angle was always 90, you would always be applying the maximum amount of force to the crank.

The difference between cylinder wall loading between 5.565" or 5.7" rods in a 3.75" stroke motor is about 0.8%, hardly enough to cause major damage.

veno
31st-December-2008, 11:18 AM
no interest in my 383 FE based engine? 4.3 bore and 3.3 stroke

69NovaSS
31st-December-2008, 12:52 PM
no interest in my 383 FE based engine? 4.3 bore and 3.3 stroke

I'm interested...but with that short stroke how is it going to make any torque????:rolleyes::D

stock z/28
31st-December-2008, 02:35 PM
Hello Mike,


Tell me more about your class win. Thats an impressive feat for any combination.


What class were you running?


Thanks

Jeff

Mike Goble
31st-December-2008, 02:54 PM
It was F/S and all I had to do was beat the other car in the class. They used to hold the AHRA Winternationals at Beeline Dragway the week before the NHRA held theirs in Pomona. I lived about 5 miles from the strip at a trailer park in Fountain Hills.

Camgrinder
31st-December-2008, 03:03 PM
The difference between cylinder wall loading between 5.565" or 5.7" rods in a 3.75" stroke motor is about 0.8%, hardly enough to cause major damage.

Whats the % difference between a 5.565" rod ,3.75" stroke and a 5.700" rod, 3.48" stroke?

veno
31st-December-2008, 03:43 PM
I'm interested...but with that short stroke how is it going to make any torque????:rolleyes::D

Its a red herring... 1958 383 Mercury, Edsel, Lincoln.....[MEL]

its impart based on the Ford FE block and with a 10 degree offset in the deck like the 348/409... where the piston shape makes the compression.... and the block is the combustion chamber....

levisnteeshirt
31st-December-2008, 04:55 PM
It's not intended as any sort of bashing, I'm merely trying to get you to think about the physics of the internal combustion engine.

I learned about rod angles and crankshafts early on in my life while riding my bicycle. I discovered that leaning back and creating a better angle on the pedal crank would put more torque to the rear wheel. Guys who didn't take advantage of the improved angle got left in the dust.

The ideal connecting rod would be no connecting rod at all. If you could design an engine with the piston connected directly to the crankshaft so the piston/crank angle was always 90, you would always be applying the maximum amount of force to the crank.

The difference between cylinder wall loading between 5.565" or 5.7" rods in a 3.75" stroke motor is about 0.8%, hardly enough to cause major damage.

i've saw some short ( 5.565 ) rod 383's go through some torture and keep coming back for more. 3 years in a round tracker, served time in a drag car after that and was never took apart till it was sold. If you listen to some people , it should have exploded its first trip to 7000 and never did.

Mike Goble
31st-December-2008, 10:13 PM
Whats the % difference between a 5.565" rod ,3.75" stroke and a 5.700" rod, 3.48" stroke?

According to Rick Draganowski's rod study, the 5.7/3.48 setup transmits 32.05% of the force to the wall, while the 5.565/3.75 transmits 35.64%, a difference of 3.59%. This would be at the maximum rod/bore angle.

tnblkc230wz
31st-December-2008, 10:30 PM
This has been an interesting thread. What force would be placed on the cylinder walls with a 3.875 and 4.00 inch stroke with a 6.00 and 5.70 rod? If your going to stroke your motor, why stop at 3.75?

Mike Goble
31st-December-2008, 11:14 PM
The load on the cylinder wall is roughly proportional to the sine of the rod/bore angle. A 4" stroke would have a maximum rod/bore angle of 20.34 with a 5.7" rod and 19.47 with a 6" rod. This occurs at 90 from TDC, so the cylinder pressure is far from its peak. The 5.565" rod/3.75" stroke setup has a maximum r/b angle of 19.69, not much more than the 6" rod/4" stroke combo.

Tubbed63
1st-January-2009, 11:56 AM
I would take a 377 over a 383 any day of the week. Scream it out of the hole and wing it out through the gears. This is comeing from somebody that has a 13:1 brodix headed .650 lift 383. A properly built 377 is just plain NASTY. :yes:

Mike Goble
1st-January-2009, 12:04 PM
Do you think a 1/4" difference in stroke is going to make that much difference in the rpm? We're talking 7.75% difference here. That's 775 rpm difference at 10,000 rpm.

Camgrinder
1st-January-2009, 02:38 PM
According to Rick Draganowski's rod study, the 5.7/3.48 setup transmits 32.05% of the force to the wall, while the 5.565/3.75 transmits 35.64%, a difference of 3.59%. This would be at the maximum rod/bore angle.

That looks like a 10% increase in the force transmitted to the cylinder wall. On an engine with high bmep, it could be significant.


I typically see a 300 rpm change in peak HP going from a 3.48" to a 3.75" stroke, when the stroke length is the only change. So, if a well thought out 377 with a 3.48 stroke had a 7500 rpm HP peak, I would expect the same heads/intake/cam/rod ratio etc combo in a 3.75" stroke 383 would peak around 7200 rpm. Just a rule of thumb I use.

Pwrtrip75
1st-January-2009, 04:02 PM
I would take a 377 over a 383 any day of the week. Scream it out of the hole and wing it out through the gears. This is comeing from somebody that has a 13:1 brodix headed .650 lift 383. A properly built 377 is just plain NASTY. :yes:

same here. :yes: