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Discussion Starter #1
tying to get to 9.25-9.50 to 1 compression I think.trying to build a 325 H.P.307.procomp heads 2.02 1.60 64cc 190 runners,howard 465/485 lift cam,thinking KB flat top pistons.I've read a few articles about cutting deck height to get proper comp. but really don't know how to calculate properly.any help would be apriesiated.valve clearance problems?proper compression ? ext.ext.ext.
 

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Discussion Starter #4
cant locate the article right now but I've read two that told about going to the junk yard & finding a 307,put in a simuler cam & 2.02 heads on.dynoed at 315 H.P.skip white performance recomended cam & heads.I sure hope will work.
 

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To achieve a static compression ratio of 9.5:1 with your 307, Pro Comp heads, and flat-top pistons you will need to bore the cylinders +.030" (3.905"), zero deck the block, mill the cylinder heads approximately .050", and install a Fel-Pro 1043 head gasket (.039" compressed thickness, 4.080" gasket bore diameter).

You're going to want to build in as much static compression ratio as you can with this engine build. The 190cc runner volume of your Pro Comp heads is quite large for a 307 engine, and low speed torque production is going to suffer unless you pack some compression into the engine. I'd search for a set of N.O.S. or good used TRW dome pistons for your 307 (part number L2272F). You can build this engine with a static compression ratio in the 10.5:1 - 11:1 range and safely run on 91 octane pump gas without any issues. The aluminum heads are going dissipate heat from the chambers more rapidly which will effectively increase the octane tolerance of the engine. Also, the 307 features a relatively small bore diameter which will help contribute to improved detonation resistance, and will also require less total advance for peak power production.

I'd look to a single pattern cam profile, preferably something in the 218 - 220 duration range at .050", and on a tight LSA like 108 degrees. This type of cam profile will significantly improve low-speed and mid-range torque production as well, especially if you build the engine with a higher static compression ratio.
 

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Discussion Starter #11
thanks for the info pete63.the cam i have is a howard 465/485lift 225/235 duration @.050" and110 lobe sep.you think that would work O.K. or should I get anouther? could be diff. finding pop-ups for a 307.not the most popular bore size in the world.read a few things about boring to a true 4.000 and building into 327,but that 120 bore sounds a bit much to me. besides that ,part of the fun was seeing how much I could get out of this 307 on a low budget.do you know of any problem with the 2.02 valve clearance in cyl.
 

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i don't think a 2.02 head is going to fit that bore...

start milling heads and block to achieve a higher comp ratio and intake milling comes into play too... then you'll find all your specially milled items are now all "Special" parts due to milling and they're not going to ever be good for use on any other engine combination... i don't think i'd waste the money on a 307. yeah yeah yeah, do what you want to do but have some common-sense about the whole thing... go buy a 350 block and save all the money on special machining and be done with it...
 

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I have to say this, and hope you don;t take it personally. if it comes across harsh, I'm sorry.

What your doing is not worth the head gaskets your going to waist. :rolleyes::rolleyes:

Your wasting a lot of money, time and work.

For the money you spent alone on your heads you could have easy found a 350 block and have the HP, torque your trying to achieve. And most cases more.

A 307 is just what it is, a 307. You can't make chicken soup from Chicken S**T. The ******* 307 is a long arm 283 engine and just happen to make torque at low RPM, and that's all it's going to do and ever will.

And on top of this you going to put new pistons in it?

And 325hp from cheap parts and a 465/480 lift cam shaft on a 307 is never gonna happen.
IT"S NOT GOING TO HAPPEN! :no::no::no::no::no:


You will do all this work and some kid in his old Mailbu with a wore out 350 and headers is going to dust your butt!

350 gen1 engines are available and you just might luck up on one that's not hurt and a cheep rebuild will get you results.

PS: Good luck with your cam and the "CHINESE LIFTERS"
The head casting are not bad, but Skip does use PRO COMP CHINESE valves and springs. And when you drop a valve your engine will be garbage! I say WHEN, not if, when, it will happen.

A broken valve 99.9999% of the time the most catastrophic engine failure.
In the end you take your intake, and valve covers and toss the rest.

============
I can respect your budget, but your spending money that can be better spent and get results.

I say this with experience, experience of spending your money and it's wasted.

JUNK IN = JUNK OUT

IMHO
Al



Let me give you some info, if you going to purchase pistons, all you need is a block, everything (EVERYTHING) Form your 307 can be used. All you need is block and pistons.
 

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My 260 horse crate 350 was faster in the quarter mile than my 218/218 .460/.460 cammed, ported 305 HO heads, 1.6 roller rockers, etc etc etc 307. I would also advise finding a 350 base to work from, if possible.

If not, the 2.02 valves either won't clear the bore or will shroud the valves quite a bit. A lot of times guys would open up the top of the block to make it work on the 283 combos. I'd test fit before running it.

I'm also leery of the Skip White valve train.

Kev
 

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thanks for the info pete63.the cam i have is a howard 465/485lift 225/235 duration @.050" and110 lobe sep.you think that would work O.K. or should I get anouther? could be diff. finding pop-ups for a 307.not the most popular bore size in the world.read a few things about boring to a true 4.000 and building into 327,but that 120 bore sounds a bit much to me. besides that ,part of the fun was seeing how much I could get out of this 307 on a low budget.do you know of any problem with the 2.02 valve clearance in cyl.
Boring the 307 block to 4.000" is possible with certain castings, but you'll have to sonic test the cylinder walls for thickness before determining if your block will withstand a 0.125" overbore.

The cam you have features quite a bit of duration for 307 cubic inches and a 190cc head. Again, if you're going to press on with this build you're going to need to have as much static compression ratio as possible.

You may have to notch the tops of the cylinder bores for additional intake valve clearance. This is something you're going to have to check during the build. You will need to mock up the heads on the bare block and check valve-to-bore clearance accordingly. The low-lift camshaft may allow the 2.02 intake valves to clear with no modifications, but I cannot verify that with 100% certainty.

I agree 100% with everybody that suggested using your parts with a larger displacement short block such as a 350. Also, I don't know anything about Skip White but if you're using Chinese valvetrain parts you're asking for trouble, just like the other guys indicated. Something else to be aware of... Pro Comp heads feature the world's worst valve job and very low quality valve seats as delivered from China. At the very least you're going to want a competent machine shop to redo the valve job before running those heads.

All that being said you didn't ask if you should build a 350 so I wanted to answer your original questions as accurately as possible. Is it worth building from the perspectives of return-on-investment or horsepower-per-dollar? Not really. Should you build it anyway just for the challenge of it? That's up to you, but don't expect stellar results unless you build it with quality components, quality machine work, and proper assembly procedures.
 

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I have to say this, and hope you don;t take it personally. if it comes across harsh, I'm sorry.

What your doing is not worth the head gaskets your going to waist. :rolleyes::rolleyes:

Your wasting a lot of money, time and work.

For the money you spent alone on your heads you could have easy found a 350 block and have the HP, torque your trying to achieve. And most cases more.

A 307 is just what it is, a 307. You can't make chicken soup from Chicken S**T. The ******* 307 is a long arm 283 engine and just happen to make torque at low RPM, and that's all it's going to do and ever will.

And on top of this you going to put new pistons in it?

And 325hp from cheap parts and a 465/480 lift cam shaft on a 307 is never gonna happen.
IT"S NOT GOING TO HAPPEN! :no::no::no::no::no:


You will do all this work and some kid in his old Mailbu with a wore out 350 and headers is going to dust your butt!

350 gen1 engines are available and you just might luck up on one that's not hurt and a cheep rebuild will get you results.

PS: Good luck with your cam and the "CHINESE LIFTERS"
The head casting are not bad, but Skip does use PRO COMP CHINESE valves and springs. And when you drop a valve your engine will be garbage! I say WHEN, not if, when, it will happen.

A broken valve 99.9999% of the time the most catastrophic engine failure.
In the end you take your intake, and valve covers and toss the rest.

============
I can respect your budget, but your spending money that can be better spent and get results.

I say this with experience, experience of spending your money and it's wasted.

JUNK IN = JUNK OUT

IMHO
Al
:yes::yes::yes: What Al said!! :yes::yes::yes:

:ragtop:
 

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:yes::yes::yes: What Al said also:yes::yes::yes:
 

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if your going to purchase pistons, all you need is a 350 block and 350 pistons, EVERYTHING else from your 307 will work.

All you need is 350 block and pistons. :D

FYI
Al
 

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if your going to purchase pistons, all you need is a 350 block and 350 pistons, EVERYTHING else from your 307 will work.

All you need is 350 block and pistons. :D

FYI
Al
The 307 has a 3.25" stroke crank. A 350 block and that crank will give him 327 with the correct pistons.And yes,the rods and all else will work.:)
 

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I ran 2.02 heads on a .30 over 283. I dropped a 327 crank in it. Basically a home grown 307 (311 actually). It ran very well with those heads. It wasn't going to be a barn burner but it was fun when I was a teenager. I would agree that in the horsepower per dollar calculation it's not wise.

But then again sometimes I think people wanting to do something different (run a small engine) get beat up a lot in the Chevy world. Could there be anything more boring than a Chevy 350 (probably sacrilege to some)? :eek: Slap it in a 69 Camaro and we have the perfect boring combo.

I do remember a winning Engine Masters 307 some years back but of course that was a professional with some trick work.

Maybe I'm just getting old and I like when people do something different.
 
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