marky mark

Was trying to think of as many possibilities for a new motor as I can and avoid paying so much $ that it all entails.

So, here's the idea: GM 502 shortblock.
"781" oval ports w/ large valves and some porting, etc.,
approx cc 114 = approx 9 to 1 comp ratio.
stock GM low rise alum intake (L-36 motor).
Quadrajet worked on some more by Lars.
Hooker 1&7/8" Supercomps.
2&1/2" duals w/ X pipe, Dynomax super turbos.
'69 ragtop, 4 spd., 3:36 gears.

The more I think about it, the more this seems to make sense. Essentially a lower budget 502 than the 502/502.

It would have the better cam than does the 502 HO and the oval ports which are probably the best oval port style of factory heads made (not the best out there of course). Should make a very streetable combo.

I know the low tech nature of old iron oval ports, low rise intake and quadrajet might not be the best idea, but if I can save a couple thousand why not? I would expect to give up some power but not sure how much really.

Plus, this combo will fit under the stock big block hood!

Any thoughts on this plan will be certainly appreciated.

Regards, Mark :chevy :flag

Glenn454

I't should work fine with oval ports. I run factory ovals with port work and 2.25 Intakes and 1.88 exhausts. My combo has pulled 450rwhp and 490rwtq In a 454.
I'm running a healthy Hyd roller and 10.5 compression. You might want to run a torker II Intake, It will fit under a stock bigblock hood.
Sounds like a good combo, should make tons of torque. :)

marky mark

Glenn,

Thanks for the reply. I was also thinking of perhaps using a set of iron rectangular ports and a low rise intake from the LS-6 days. Then I could run a Holley carb. I shy away from the Torker 2 because what everyone says abot low rpm response not being good (single plane).

This would not be an engine that spins past 6000 rpm so the rect port heads may not be worth the investment.

I am trying to consider all my options.

You have one very powerful motor by the way. Those #'s are very impressive! I could save even more $ by buying a 454 shortblock instead of the 502.

Thanks, Mark

427Hotrod

I have a friend with a homebuilt 502 using iron Gm oval ports in a sort of street racer type Camaro. The heads have larger valves and are ported VERY nicely, uses a Lunati hyd. roller cam and runs 10.20's in a 3200# car with a 2500 converter and 3.73 gears. It engine dyno'd at 610 hp. He shifts it at approx 6400 or so.

You may well be on to a good combo. *IF* you use a low rise intake and a Q-jet, you're never going to flow enough air to feed large heads anyway, so you might as well build a TQ monster.

The GM rectangular ports would also work well IF you cam it right and use the LS-6 intake and Holley.

If you use the oval ports, they will need a lot of port work, but they can be made to flow very well!

Don't be afraid to sneak up on 10.0 compression and don't go too small on cam. Feeding 500+ cubes is something GM didn't plan on with either oval or rectangular heads. You're going to have to help them out some even with a lo-rise intake and Q-jet.

That stock intake can be ported too you know!

Please seriously consider "at least" 2"headers. The 1 7/8" are too small. And if you haven't run new pipes yet, 3" would really help it out. 2 .5" is gonna choke it bad.


JIM


[Modified by 427Hotrod, 12:11 AM 8/18/2003]