The 400 small block is a great motor if a few things are done. You with out a doubt need 5.7 rods, and little grinding is needed, but not much. You also need to drill steam holes in the heads, this is easy though, just line up your gasket, mask, take gasket away, and drill. you can get really good power down low, with a good, smart cam, head combo this thing will make crazy power>