[Mark O'Neal]

Any 351W crank will fit, the differance is in the slinger height at the rear main seal. A two piece has a taller slinger so you'd have to cut it to fit a one piece block. A one piece crank will fit in an early block.

If you get a 12" caliper you can measure from the bearing saddle to the deck of the block. Add that measurement to 1/2 the size of the bearing hole and there's your block height.

You should do it at all four corners......