How much power does this make? I'm going to rebuild the 350 in my IROC. Bored .030 with a good cam. I'll probably use the stock heads but I'm want to port match the TPI runners to the heads and intake, plus siamese them.

I'm not asking about the power of this vague combo just the amount usually picked up by siameseing the runners and port matching.

Also would it be worth porting and polishing the stock heads or would it be better to get an aftermarket set?

Thanks

 

The amount of power it makes is relative to the rest of the engine combo. My particular setup made only 10 more horsepower at the peak, but it did it at 700 rpms higher than with the regular large tube runners.

The stock heads suck. Get an good aftermarket set such as the Trick Flows.