Will a 3.8750 crank Fit? [Archive] - Chevy Nova Forum

: Will a 3.8750 crank Fit?


askgene
24th-December-2008, 07:46 PM
Ok guys where are the engine builders the real small block guys,I have a nice little 406 thats all cast,I really overheated it a coulple times,forgot to turn on electric water pump it never stalled,but think I coulda hurt it somewhere.Althought it runs great only has 10,000 miles tops.Anyway I'm back to work and thought it would be nice to get rid of the cast stuff and rebuild it bore it if needed its only 030 over,heads are new darts,want to put either a forged scat set up or an eagle,wanna juice it maybe so all forged is the name of the game,NOW THE BIG ONE who knows if my nice 509 high nickle block will accomodate,a little weeny stork to 3.8750 up from 3.75 a 5.7 rod engine naturuly.thought a 040 over 1/8 inch stroke would be nice!! 200 shot big solid cam dart platinum 200s,lookin for 9.90s,10.2-1 compression if possible,anyone done a 3.8750 stroke please get back to me,before I make a mistake runnin a 248/248 520/520 now which cam? 250/260 at@050dur 540 lift?HELP GUYS THAT KNOW,any Joe Shermans out there?Jack Merkle,grumpy help me:(:(:(:(:(

levisnteeshirt
24th-December-2008, 07:54 PM
changing over to a solid roller is where i'd put the money. I'd say you would get more bang for the buck instead of the crank swap. I'd say you will have to with a stroke increase because of rod clearance anyway if you do increase stroke. This should be getting in the area where small base circle equipment is needed.

6NOVA4
24th-December-2008, 08:34 PM
changing over to a solid roller is where i'd put the money. I'd say you would get more bang for the buck instead of the crank swap.

I agree, go solid roller. I'd go something in the .660" 270's duration @.050" on a 108 LSA something that works with nitrous but won't be a turd without it. You may want to get those 200 platinums tuned up or maybe consider AFR 220's or Brodix Track 1's Also I think the 3.875 stroke will fit may have to do some "clearancing" to the block. So .040" over makes it 4.165 bore x 3.875 will make it a 422.3 ci you're gonna have to get new pistons anyways so it wont matter if you keep it .030" or go .040" use the 5.850 rods for better rod/stoke ratio get a piston with a good compression height, keep the ring stack down from the top of the pistons with N20.

Now if you stick with the 406 and your heads then still go solid roller and try something in the 620"lift range with 260's@ .050" on a 106 LSA

dlc1979
24th-December-2008, 08:58 PM
Might want to look around the Dart board http://www.dartheads.com/dartboard/index.php, since you're using a lot of their parts. A couple of good common sense engine builders over there who can get you steered straight.

dc

Professor Fate
24th-December-2008, 09:41 PM
How do you know your block has a high nickle content?

6NOVA4
24th-December-2008, 10:11 PM
that's what the 509 casting is. Its the high nickel content block.

69NovaSS
24th-December-2008, 10:58 PM
to answer your question yes, a 400 SBC will take a 3.875 stroke crank. (it might take a little clearancing though) heck a 350 SBC will take one too, you just need to clearance a little more;)

Ironman
24th-December-2008, 11:32 PM
400 block clearanced on pan rail and cam tunnel for a Scat 3.875 stroke crank and 6.0" Eagle H beam rods.
http://i160.photobucket.com/albums/t179/72NovaPR314/IMG_0272.jpg

CNC BLOCKS
25th-December-2008, 07:26 AM
400 block clearanced on pan rail and cam tunnel for a Scat 3.875 stroke crank and 6.0" Eagle H beam rods.


By the looks of the file marks in the main cap registers there not very flat, Thats why we machine the registers for flat bottom caps.

NOVACA1N
25th-December-2008, 10:31 AM
A friend of mine had a 4" stroke in a stock 400 block...You should be fine.

Professor Fate
25th-December-2008, 02:27 PM
that's what the 509 casting is. Its the high nickel content block.

We've discussed this ad nauseum and the current thinking is that this is an internet rumor or urban legend. Without metallurgical testing there is no sure way of knowing.

veno
25th-December-2008, 02:44 PM
I remember reading in a couple of the rag sheets and other authoritative publications.. about GM raising the Nickle and tin content on select blocks and the PN#'s....and the reasons...

for the life of me I dont recall the rags sheets or publications....

It was long before the internet created these so called rumors... and long before the Internet existed.....so you had better blame Peterson publishing for the lies...

I for one still believe it.... until some authoritative written proof exists... I will still believe it..... Now.. whether the 509 block is one of those... I have no clue.. or like the 397010 block with the 10 and 20 cast in to the timing area... to be supposed to have 20% nickle 10% tin.. or is it the other way around?.....

I never concerned myself with it..... I have a 817 and a 509 block sitten on the floor now.... so I guess I'm lucky?

missile33
25th-December-2008, 09:05 PM
It can indeed be done. However make sure you get a set of rods that are clearanced for strokers. We have tried several sets and brands and have found one that works the best. If you want a part number let me know.

askgene
25th-December-2008, 10:27 PM
changing over to a solid roller is where i'd put the money. I'd say you would get more bang for the buck instead of the crank swap. I'd say you will have to with a stroke increase because of rod clearance anyway if you do increase stroke. This should be getting in the area where small base circle equipment is needed.
OK SO i'LL STAY WITH THE 3.75 STROKE BUT GOING TO WAIT TILL i CHANGE THE HEADS BEFOR i GO SOLID ROLLER.sINCE THE PLATINUMS ARE ONLY 4 MTHS OLD AND SET UP FOR A SOLID OR HYD ROLLER.!!wHEN i GO TO BIGGER HEADS i'LL GO WITH THE SOLID ROLLER SPRINGS &
THE UPGRADE TO THE ROLLER.DO U THINK i SHOULD GO FOR 1100 FOR THE EAGLE CAST SET UP JUST WITH FORGED PISTONS,:no::no:OR SHOULD i SPEND THE 1500-1600 AND GO ALL FORGED WITH THE H RODS?:yes::yes::yes:SINCE i THINK i CAN GET THE CAR INTO THE 10.9 RANGE WITH THE SOLID FLAT TAPPET,AND WITH A 200 SHOT GO FOR THE 9.90S.i DONT KNOW :confused::confused::confused:u KNOW i JUST MIGHT BUY A 383 SHORT BLOCK AND WAIT TO GO ALL THE WAY WITH MY 406,TAKE AYEAR TO BUILD A ROLLER WITH 227 afr HEADS AND 11.0-11.3 COMPRESSION 6 INCH ROD NO JUICE MOTOR.

6NOVA4
26th-December-2008, 03:28 AM
I went 10.70's N/A with stock crank and Pink rods(5.7) and 9.50's on spray. But its up to you, spend the money once so you have piece of mind. Build a stong foundation then you can pick and choose what top end you want. You probably could find better deals for rotating assemblies out there.

6NOVA4
26th-December-2008, 03:31 AM
I remember reading in a couple of the rag sheets and other authoritative publications.. about GM raising the Nickle and tin content on select blocks and the PN#'s....and the reasons...

for the life of me I dont recall the rags sheets or publications....

It was long before the internet created these so called rumors... and long before the Internet existed.....so you had better blame Peterson publishing for the lies...

I for one still believe it.... until some authoritative written proof exists... I will still believe it..... Now.. whether the 509 block is one of those... I have no clue.. or like the 397010 block with the 10 and 20 cast in to the timing area... to be supposed to have 20% nickle 10% tin.. or is it the other way around?.....

I never concerned myself with it..... I have a 817 and a 509 block sitten on the floor now.... so I guess I'm lucky?

^^^^ what he said. Back in the day before the internet that's what I was told and also read it in a small block build up book or a magazine article. Sorry it is what it is.

dlc1979
26th-December-2008, 08:43 AM
I build 402CI or a 408CI SBC that think they are BBC engines. I own and operate Awesome Engines, a leading engine supplier for customers all over the world and yes, we have a dyno to back up and check every enigne sold and supply you with a warranty. We started the warranty program 4 years ago with the never heard of "You Break It I fix It For Free No Nonsense Warranty Program. Now everyone has their scary version of it. I back up our engines!

402CI SBC, 4.000" Bore w/ a 4.000" AERC 4340 Crank, nice square Torque Monster Engine. This engine on pump gas makes 570+ real HP and almost 590 ft. lbs of torque anywhere between 3000 and 6500 rpm with a solid lifter engine and 2500 to 6000 rpm with a Hyd roller. You get your choice of either camshaft. 6.000" AERC, 4340 Steel Rods with Wiseco 2618 real forged Nitrous o.k. pistons, all internally balanced into a brand new GM 4 bolt block that is fully race prepped to race specs. Includes Brass freeze plugs, not those cheap Chinese steel one that everyone puts in and they last now about 1 year. Brand new Dart 230 cc Aluminum Heads or RHS 235 cc Aluminum heads completely race prepped. Dual plane Air Gap or Single Plane Match Ported Intake Manifold with a brand new 750 cfm Holley carb. This would be a complete engine with HEI Distributor, wires, plugs, all assembled and dyno tested and tuned for your combination. Everything is complete with these engines and they will hold their own with any comparable engine out there. There are some upgrades you can enjoy but are not needed. $8999.00 Brand New Full Race SBC. Hows that for black and white and everyone can see. RACE READY NEEDS NOTHING, we even throw in a SFI Flexplate!

- Bill Cannon -
- Custom Drag Racing Engines & Transmissions - Awesome Engines -
Home Page: http://awesomeengines.biz


I going to talk to this guy after the first of the year about building me the above engines for my Pro Streeter. (Note it has a 4" stroke!)

69NovaSS
26th-December-2008, 08:50 AM
here is some info on a 401 cube SBC based on the 350 block

http://i56.photobucket.com/albums/g180/1969NovaSS/enginespecs/page1.jpg

http://i56.photobucket.com/albums/g180/1969NovaSS/enginespecs/page2.jpg

http://i56.photobucket.com/albums/g180/1969NovaSS/enginespecs/page3.jpg

http://i56.photobucket.com/albums/g180/1969NovaSS/enginespecs/page4.jpg

BTW if you do this build but only do a .030" overbore on the block you end up with a 396 SBC sort of cool eh?:cool:

Professor Fate
26th-December-2008, 09:34 AM
^^^^ what he said. Back in the day before the internet that's what I was told and also read it in a small block build up book or a magazine article. Sorry it is what it is.

Back in the day a 3/4 cam was the thing to have too. Urban legends are wonderful things.:D

6NOVA4
26th-December-2008, 06:20 PM
Back in the day a 3/4 cam was the thing to have too. Urban legends are wonderful things.:D

don't laugh I had what you would call a 3/4 race cam, 470 lift, 252@.050 on a 105 LSA in my LT-1 350 and it worked excellent. 11.90's@114 all day in my car.