I finally tore into my 400 Small Block in my attempt to fix the either blown head gasket or possible warped head. So far I taken off the plug wires, ac unit, carb and valve covers. Still need to take off the manifold, exhaust and heads. I did manage to obtain an extra set of heads from a 350 small block for the reasonable price of a case of beer. The heads look in fare shape but are missing two valve springs and two push rods. Should I need to use the 350 heads what would a fare price be to have them reworked and tested? I'm hoping for the best in that I'm just looking at a blown head gasket and will not need to change the heads out. Any suggestions or other things I should be aware of in the rest of the disassembly and rebuild?