Buying some 1.94, or 2.02 valves(200$) new springs(100$) that can handle .610lift. Taking the heads to the machine shop, have them machine everything and put them back together with a little porting.Or just buy a set of aftermarket usedafr,trickflow,etc?

 

For a .600 lift cam, you'll want some aftermarket heads.

 

after markey heads for sure

 

That's a lot of lift for stock heads.