humor me with some bench racing?

[joehalford01]

hey guys,

i've got alot to do before i can even get to this but i need to get it out my head so i can start planning a little. I want serious power for my 80 vette but need to remain smog complient. Stroking a motor is legal and totally passes the visual inspection. What is the maximum cubes i can reliably stroke and bore out a small block 350 and run 10:1 compression? everything held equal regarding exhaust, upgraded cooling etc. I will also be going with vortec heads and intake if i can get away with it, if not, pumped up old skool heads. I would like at least 400hp, which i think is acheiveable if i use my thinking cap alittle. let me know, thanks guys!

 

[Tripper]

Upper end kit!

Joe,
I'm in Tejas but maybe the Cal guys can help u on this & think it's legal there but... what about a Holley or Edlebrock upper end kit! They pump out about 425hp. I put one on my Chevelle & it was nice, easy & took care of business!

BoB

 

[gassersgarage]

The most bang for the buck would be what Trip said. Least expensive and reliable horsepower that is smog legal. You can get exotic by going to a 383, 406 or 427. The small block can be taken out to 454 if you wanted.

When I built my Biscayne, I was gonna go to PAW to build the engine myself. Then I remembered an old company when I was 16. www.speedomotive.com Check out their site. I couldn't build an engine for what their's cost. Engine was great and reliable.

Doesn't the 80' Corvette have a computer carb? If so, that will be your only downfall as you will be limited in cfm. Just be sure, anything you add to the engine has a E.O. number (executive order). When it comes to smog, after your modifications, if it doesn't pass, you get a one time exemption. After that, it must comply.

 

[joehalford01]

a built long block might be the way to go, thanks dude. as far as a carb goes, the 1980 ca cars had computer carbs, they wern't adopted across the board until 1981 and this is an out of state car.

 

[gassersgarage]

a built long block might be the way to go, thanks dude. as far as a carb goes, the 1980 ca cars had computer carbs, they wern't adopted across the board until 1981 and this is an out of state car.

Then TALLY-HO and lets get crack'n.........

Hows she handle and do you like her? Whats the wife think?

 

[joehalford01]

i frikkin love this car more and more every time i get behind the wheel. it handles like it's on rails but then again i havn't driven too many high end sports cars for a good comparison. My wife loves her too. i'll have to get some more pics up for you guys.

i have to say though, with the way the front end is shaped, it's like sitting in a missile behind the wheel

 

[Tripper]

Be careful!

i have to say though, with the way the front end is shaped, it's like sitting in a missile behind the wheel

Joe,
Be careful... on my way in to work one day on a very intense freeway... I saw a 'Vette that had not stopped in time & slid up under another car... the cars back wheels were up on top on the 'Vette's hood with the rear bumper inches from the windshield. Scared me!!!

BoB

 

[joehalford01]

EWWWWW.....scary. Don't worry, i won't be totally stupid driving it around. Wont do me much good if i lose my license and my wife gets to drive it everywhere .

 

[LordMaximo]

Well it depends at what you can afford.
First off, a 350ci engine with a bore and stroke of 4.000 x 3.480 will net you ~300HP@4800RPM, using just a 4 BBL. And then again, you will have the option of cam grind to figure into your build. This can net you even more HP but makes it touchy on the emmissions.
Now if you run a fuel management system with a coil per cylinder and injection, you can add about another 50HP with a tuned exhaust and a cut rate program to make the best of your configuration. So your EMS will need a couple programs to pass you through the inspections and then you retune it for your sort of driving.


Good luck,

Maximo

 

[joehalford01]

well, i've done some more research and i need to find one little piece of info. i don't know what the stock head cc's were. Right now i have 9:1 compression and a mild cam. 230 horsepower is the stock rating. i think if the cc's are higher like 72cc then dropping to a 64cc should net me some more compression, throw in a dual plane manifold, and a slightly bumped up cam that will idle at 9 degrees timing i hope i can get at least 300hp. this may be the the way to go until i get the money for a built motor.

 

[LordMaximo]

The information I gave you is a stock build from a 1969 Corvette 350 engine.
The information came out of the 67 to 76 Chilton's book, I do not remember any cam ratings, but can chech once I get home tonight. Most of my engines are from the mid 60's to mid 70's engines.
I try to build everything to the late 60's ratings, all muscle builds.
Max HP

 

[joehalford01]

i totally appreciate the info too, throw anything you got at me because i'm still pretty new at this engine internals stuff. I've grown up in the age of chips and turbos where you just buy a new motor when the old one blows up.

I did find out though, the stock heads are 76cc smogger heads! Thats awesome! It already has 9:1 so with a thin head gasket and some 64cc heads i should be at just a little over 10:1. I may go with the cast iron 67cc summit heads though for price. Edelbrick aluminums are 600 each whereas the summit cast iron are a little over 300 each. Not as much power and more weight but i could fit it into my budget a bit better. Hmmmm......decisions, decisions.

 

[LordMaximo]

If you can find some old heads from a Chevy 265 ci engine, those were the small combustion heads. I found that these heads will offer up super compression to a built SBC. Add some domed pistons with valve reliefs and 0.100" worth of copper gasket, and then bam, there you go, a real fine HP increase on a shoe string budget.
I would reccommend doing a fine tune on the valve job, add a dual spring with internal dampner to the valve train and use of some 1.5 roller rockers, you can then dial in the performance you want. Nothing can compare to a good set of heads that are built for breathing and with out a good set of heads, that big bore and super cam arn't worth the money spent.

The only problem with these old heads, is you can't use them on wide bored engines, that being anything over a 4.000" bore, not enough room between the pistons. These heads were made for the small bores, 265ci to 327ci engines. The 350ci is at 4.000" stock bore, and this is max can take these heads. So your build, if using the small bore, high compression heads, you need to look at the stroke and piston configuration being incorporated. You can always add thickness in the gaskets to actually help balance the heads with the stroke. Most times it is the heads being shaved to increase the HP on a close to stock build. This has always been a simple trick in gaining a few more HP with a minimal amout of cash. Good luck on the build, Maximo