I am trying to find out the general specs of tpi heads. I just bought a motor that has a set already on it, but I want to change the cam and intake and things, and want to know what exactly I am dealing with. I dont know whether the car was a 5.0 or a 5.7, but I do know it was an 87 pontiac formula firebird. I need to know whether the 5.0 and 5.7 tpi heads were different, also the stock valve sizes and the chamber sizes. I was told by the previous owner that they were 194/150 valves with 64cc chambers, is this true? Also, are these a good flowing head or would I be better with an older 202 head or something? Any help is appreciated, thanks.

Zac

 

if it had 194 valves then it was a set of 350 heads 184 came on 305.

it all depends on how radical you want to get with the motor. what are you trying to achive.

 

well, he said it was an 11:1 compression motor which seems kinda high, but I was wanting to pull about 400-450 horse out of it. It was a tpi motor, but now its gonna be carb. I am thinking about going with an Edlebrock performer RPM intake and cam set, which puts me at the 1500-6500 rpm range, with the cam being like 512 lift on both, and a 230 duration. what do you think?

 

Yes, the 305 and 350 heads were different. 305 TPI heads had 58cc chambers and 184/150 valves. With 64cc chambers and 194/150 valves they are almost definitely 350 heads. If the motor is an '87 they're probably 083 castings.

Stock 083 heads flow pretty pathetically. If you DIY port them they'll flow about 205-210 int. and 140-150 exh. - unless you install larger valves. I don't think you'd get a 400 hp 350 from your setup.

With 202/160 valves and a "good" port job you might get 245 int. and 180 exh. out of them. That should get you to 400.

 

If it makes any difference, the motor is a late 70s 4 bolt block that been bored 40 over, has forged pistons, the rods have been shotpeened, and chamfered. And supposedly, the whole motor had been balanced and blueprinted.

 

cast number is 14101081

what specs does that head have?

 

check out MorTec, Inc. Home Page it should tell you everything you need to know about castings.

-Jim

 

if the block is a 350 with flat tops then you are gonna have big compression with those 305 heads. I would port them to the max or get a set of aluminum l98 heads.

 

So, In the case that I were to get different heads, are these 305 tpi heads worth anything. They have had a valve job done, and been port matched to the lower intake. And all of it has slightly slightly under 2000 miles on it, everything is super clean. And of course the lower intake would go with it, but unfortunately, I didnt get a plenum. Also, where could I get some of these L98 heads you speak of and what exactly are they? Keep in mind, the motor is to be carburated as of right now. I dont foresee it going back tpi.

 

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