i have a 350 tuned port, what will it do if i put 305 heads on it, will porting them of course, what will the compression do, and can someone direct me to a website where i can find out more information about heads. thanks

 

The 305 heads have smaller valves and smaller combustion chambers. The compression will jump up to like 10.5 or so, but more importantly is the valve size. You will increase low end torque by increasing the velocity, but lose overall flow which will decrease the top end power.