318 head???

I have a 318 engine runs, I have a set of rebuilt 273 heads. (new unleaded value seats, new 340 springs). I will be adding a purple shaft cam.

I have been told that the 318 heads donot create great compression because of their shape.

Would changing from the 318 heads to the 273 rebuilds heads help or hurt the engine?

Additional information 4 barrel carb, duel exhaust.

What does everyone think???

Thanks,

Sam