Hey Kent, Are the 420 block and the 560 block about the same size? I found a valve cover thats off a 560 that will fit my 420. Are the block and heads the same, just the stroke is different.I am going to pick and pull tomorrow for the valve cover and safety belts. Should I just grab the engine and use some parts for my 420 or even put the 560 inplace of the 420?