I came across a LQ4(iron 6.0) for $600 plus $200 for the heads if I want them. Is that a good deal? Should I use the heads as is or have them P&P? Would there be any benefit since I will be running 15 psi?

Also, I just picked up a Callies Dragonslayer 4" forged crank and I already had Billet Oliver rods so now I just need some pistons. What do you guys recommend and what cr?