What is the most aggressive cam that you can run with stock heads? Just a basic cam swap? I understand there will be many different oppinions. I would like to pick up a few pony's and not break the bank or go to deep into the motor. Plus have a little rumpity rump.

 

its not the heads that are limiting you first, its just the valve springs... then theres the stock converter.

 

Read the cam sticky at the top of the page. It has everything you want to know, and then some.