From every indication I see it looks like you would need the crank and rods and machine the block to accept a narrower thrust main bearing. Block off the oil feed going to rod dipping tray ( that's the best name I could come up with) and put things back together. I guess you could remove the "rod dipping tray" but I don't think it would hurt anything if left in.
I can't bring myself to do this conversion to my engine. It's in too good of shape!
