calicuttc

I recently bought a 91 camaro with a 350 bored over .30,with 305 heads on it. The owner said it was to "tame" the car for his Girlfriend. which it obviously did. I barely beat a stock 98 mustang gt on 2 runs.
It has a edelbrock 650 carb and intake. so naturally I want to put edelbrock 64cc heads on it. Does anyone know what type of horsepower gains I will get just by replacing the heads?

Rice Killer87

What kinda cam is in it and what intake?

Im guessing between 10-15 and maybe 30 on a pretty modified engine.

calicuttc

hmm I was expecting more after replacing such small heads on a big engine, with its normal size heads. 10-15 hp just isn't worth $1100.
He said he did have a modded cam in it, I'm not sure what it is though.

Zepher

most people put 305 heads on a 350 to boost up compression.
You may possibly lose power or gain nothing if those 305 heads are 58cc.

takeoffeh

I ran ported #416 castings on a MILD 350 two yrs ago. Cam was 214@ .050"----.442" lift. 750 Holley, Performer intake, stock manifolds and single 2-1/4" exhaust. It ran 14.18 @97! OK, not fast, but it surprised the crap out of me, considering the stock parts it ran. I really wanted to see what shorties and 3" exhaust woulda done! (Had to pull motor because of noise, turned out to be timing chain slapping cover. DOH!)
Point is, if the cam is matched to the RPM potential of the heads (5000 in this case), it'll do alright.

Rice Killer87

Its hard to give an estimate when we dont know what we're dealing with. In order to make the most HP the engine COMBINATION carb,intake,heads,cam,convertor,gears,etc) has to work together.

You need to find out the cam specs and what type of pistons are in there to get a compression ratio.

calicuttc

I think I"m just gonna go ahead and buy a crate engine for it. I just raced again agianst my 225hp mustang and got stomped. I don't even think its a 350. more like a 308...with 305 heads on it.

ws6transam

I made 262 RWHP out of a 305 with those heads. That's about 308 at the crank.

The 305 heads have nice, tight ports for high velocity but you have to port them. You can squeak 180 to 190 cfm out of them on the intake side, which is about as good as a decent stock 350 cylinder head. With a high port veliocity and high compression ratio, they are probably good for making torque. I remember waaay back, twenty years ago, Summit Racing Equipment used to build their own engines: A 325 HP 350 smallblock that used ported 305 heads, for about $1300 or so.

If you have access to a die grinder, you can wake up the engine with an upgrade to a 1.94 intake valve and some good pocket porting. Add an XE262H cam to it and you should be good to go for some high 13's in the quarter mile.

Here's some documentation for you:
http://www.ws6transam.org/ported.html

NightTrain66

yep, if the car has small chamber 305 heads on it and you are not getting detonation, you might not see any gain.

Sure the Edelbrocks flow better and have larger ports/valves BUT you would lose compression PLUS aluminum dissipates heat much faster so to compensate you have to run about 3/4 to 1 point of compression to make up for this on a SB Chevy.

you could "effectively" lose 1 1/2 to 2 points of compressiona nd that is ALOT of TQ and about 25 HP right there.

the Edelbrocks would gain flow and offset some of this 9maybe most or maybe all and then some) but you would not see a huge gain by any stretch.

Lloyd