I might be able to get a good set of used heads from a friend for cheap. I was wondering if I had them ported, installed larger valves, and had a 3-angle valve job done to them, how much power would it gain? other mods listed below, thanks.

 

not much. 10-15 hp probably. need a cam too

 

Head work is something that should be done not just in concordance with many other factors, not just to gain some quick horsepower.

When porting your ehads and doing a valve job, u have to consider many things... Cam selection, RPM limitations, N/A or forced induction/n20 applications, valve-train etc.

Large Horse power gains from engine work are usually noticed when Heads, cam, valvetrain, rotating assembly, etc are all considered together in order to obtain certain HSP goals.

 

Go with a cam first. If you can pick up the heads cheap and they flow well then by all means grab them, but you need to consider which cam you're going with.

Did your sig say the 306? What lift is that good up to? That should be a factor. When I was going with P&P heads, it didn't matter what they flowed at .600 because my cam is only good up to like .525 I think. So that flow # mattered.