you can use SB pistons and Eagle makes some nice H-beam rods for the 4.3. about 450 for the rods. Used to could get nascar heads from GM but are discontinued and would only work with a carb. but we (Nitrous Outlet) make an adaptor to use throttle body on Holley 4150 flange intake. would love to get Hogan manifold with elbow and 78/90mm throttle body. then have to buy fuel rails, injectors and a pcm to run it all......wow, just spit out like 4 grand in parts didnt i, lol