you want atleast a 01 block any 6.0 block older than that you cant bore out more than .oo5. I had all my work on my truck done at (www.speed-eng.com) they do good work. There building 2 4wheel drive ext cabs on 36s right now. ones getting 6.0 swap forged internals lunati rods cam patriot heads and a radix it supose to be around 600hp. then the other truck is doing a built 5.3 for lots of nitrous. There just trying to get there name out right now so there doing stuff cheap.