[DMAYS@TRIAD.RR.COM]

I Am Planning To Build A Sbc 350 , 4 Bolt Main. I'd Like To Get The Most Horsepower As Possible. I Have Three Sets Of Heads Avaliable To Me No Cost. The Castings #'s Are As Follows: 376450/354434 (60cc - 1.72/1.5 305 Heads).3998993 (1.94/1.5 75cc Gm Crate - Not Mexico Heads). & 3795896 (1.72/1.5 60cc 283tri-power/ 327 250hp).

[70ChvyNova]

If I had to choose between the 3, I would go with the 1.94 1.50 heads. They have the biggest valves.

[curtis73]

The 305 heads are absolute junk. The most hp you could get in a 305 was 210 and that was asking way too much from the heads. Pathetic doesn't even begin to describe them.

The 896s were used on an engine that made 250 gross hp which is only about 190-210 by today's standards. They have terrible 40-year old technology.

Of those three I would have to go with the 993s, but they might need some serious port work. They also have large chambers which mean you'll need domed pistons to get a decent compression ratio. Even so, they should support 300-325 hp.

I guess what I'm trying to say is that there is a reason they are all free HP costs money.

You'll also have to really think about your goals. Just saying "the most horsepower possible" is like saying you want the best paint color or the best looking wheels. The small block is capable of well over 1000 hp in race-only applications but you have to be realistic with what you want. More horsepower means less low end torque, difficult tuning, no power brakes, high idles, overheating, race gas, broken drivetrain components, divorce, empty wallets, and homelessness.

How about starting with a budget, the car its going in, and what the intended use of the car is.

[curtis73]

More info on the crate heads

3998993 350 1.94 / 1.5 CFM inl 150 / exh 91
3998993 75cc chamber. Low performance cars & trucks 350 Crate motor, current, Hecho En Mexico, 159/64cc ports

I take back what I said... if they only flow 150/91 then they'll never support 300hp. More like 220 tops.

[70ChvyNova]

yea I was going to say niether of them are that good, but since you can get them for no price then I guess it doesn't matter.

[onovakind67]

Originally Posted by curtis73

More info on the crate heads

3998993 350 1.94 / 1.5 CFM inl 150 / exh 91
3998993 75cc chamber. Low performance cars & trucks 350 Crate motor, current, Hecho En Mexico, 159/64cc ports


I take back what I said... if they only flow 150/91 then they'll never support 300hp. More like 220 tops.

They will flow a lot more than 150/91. Brzezinski buys the 993 castings for his business, so I'd assume that they are similar to the 441's that flow in the low 200's @ .050" lift. This flow should be able to support 400 hp.

[curtg21]

I'm running a set of the 993's that have been ported. I bought the 355 engine already built and it makes approximately 400hp. It has a .480 lift cam with 1.6rr(.512lift), victor jr. intake, 9-3/4-1 cr., holley 650dp, and the ported 993's. My 73 camaro has run 12.41 @ 107.5 with a 3000rpm stall converter and 3.73 gears.

If your heads have already been ported or you are porting them yourself, I'd give em a shot. If not I would probably save for a better set.