75 350 rebuild

[brad75]

Hi guys!

I'm thinking you guys are probably getting tired of me picking your brains by now. I'm just trying to learn more, so stay with me here.

I have a 75 Supreme with a 350 that has performance issues.
I want to rebuild the engine(even though it is in pretty good shape right now(for stock). I plan on driving for pleasure only, but it needs some balls. The plan is to do the cam thing, Performer intake,and maybe headers. Right now it has #8 heads,which I will change to 7A's. Question is, do I need to change out pistons too? What kind of compression will I have if I don't? Just trying to make an informed decision before I throw money at it. As usual, car budjet is fairly tight. Thanks in advance for your help!


Brad75

[ragz442]

I'm not an engine guru, and can't crunch all the numbers for you on the comp. ratio etc, but I believe that they lowered comp. in the smog heads by increasing the combustion chamber volume, the pistons don't have that big of a dish. My stock '77 350 block has #6 heads, I don't see why you would need to change out the pistons. Just by adding the 7a's, good intake and carb, and a nice flowing exhaust, it will really wake it up on the cheap.

[brad75]

Thanks for the input! Still trying to make up my mind...........

[44teetwo]

I have a 75 Supreme and a 79 with an early 350 (68-72). The 75 is a gutlass wonder though it drives real nice! the early 350 in the 79 can run circles around it. I would say if you aren't worried about the numbers matching thing just find an early engine and do the swap. I was going to drive the 75 a while before I parts it out but after driving the 79 last night I think the 75 is going to become my parts victim sooner than I planned. I need the 75 for my 75 Hurst. the truth is the 75 isn't as quick as my 95 Supreme convertible and thats a 3.1 6:eek: