heads
Ls6 243 or 799 casting...they can be found used for $350-450...heck I sold a pair with the lightweight valves zo6 heads for only $550!! But they at good heads, they have bigger/more efficient ports, higher compression ratio, and if you get a pair with yellow or blue springs they will be able to handle .550" lift on the cam...next step up would be $1200 cc ported stock heads or you could send a pair of ls6 heads to AI or tspfor like $750...but I def noticed going from ls1 heads to ls6, maybe not aftermarket hp wise, but you can feel it especially wih boltons
