Jim85IROC

iTrader: (2)

Right now I'm running 461 fuelie heads, and hopefully next year I'll be able to buy some real heads. I had planned on 64cc heads to maintain my 10:1 (or somewhere thereabouts) compression, but then it occurred to me that if I lowered my compression, I could stuff a blower on without fear of fragging the motor. So now I'm tossing around the idea of getting 76cc heads and running forced induction. Anybody have any opinions about this? What compression will this yield?

camaro_1983_383

check the specs on your pistons for the c.r.

CamaroDriver

Here's a link to a calculator. http://www.smokemup.com/auto_math/compression_ratio.php

With a 4" bore, 3.48 stroke, flat tops with 6cc's of valve relief (4 reliefs), .040" gasket and the stock .015"-.025" of deck height will yeild ~8.5:1

As far as the opinion goes...... as long as that's what you plan to do (use a blower) then it'll work great. Even if you used nitrous, it'd work well for that also.

If you decide not to use a blower, you'll be kickin' yerself in the rear, 'cause with 8.5:1, you're not gonna get very good power, OR mpg.

Mark A Shields

I dont' have the program on this computer, but F-Bird'88 has posted a link to a free compression calculator on here , search for compression, and you should find it, good luck.

F-BIRD'88

You already have good heads. You can improve them with porting and 2.02 x1.60 valves.

Y not get the the blower and then swap pistons for some forged
D-dish (Speedpro) ones to lower the cr to run with the blower.
You'll kill two birds with one stone and I't will be better and cheaper over all.

rjmcgee

Or you could just trade me strait across, you heads for my 76cc heads.

doc

I'm with CamaroDriver on this one, you got to know for sure that you will install a blower, then the 76cc heads is the way to go.

I'm in the same boat, I got a 4 bolt main block sitting on the garage floor. I've been thinking about a 395 (just to be different than a 383) and a SC. Without a SC, I would want a CR of about 10.5:1, with a SC about 8.5 to 9.0:1. I need to decide on the final makeup of my engine before I buy parts.

Jim85IROC

iTrader: (2)

Right now I'm just in the decision-making stage. I'm going to save my money for a while and buy everything at once, so regardless of which path I take I'll have everything well matched. Because those heads will basically be useless for any n/a application, I probably won't go that route. If I ever went n/a, I'd need new heads. I think I'd probably be happy with my n/a power until I could afford to build a low compression stroker motor.

But, it's something that I'm considering. I do know beyond a shadow of a doubt that the junk 461s need to go. They don't flow as well as anything available in the aftermarket, and there's no way I'm pissing money into them to have 2.02s cut in. In 100% bone-stock condition, they're worth a few bucks to people with fuelie Vettes, but once I screw with them they're worthless. They flow well for a stock casting, but their flow won't ever match what I can get from AFR. I also want to re-install my air conditioning, and I can't do that with these heads.