I went and got the crank today. Used Callies, 2.375 rod pins, 4.5 stroke. If i can find a set of good, strong 6.76 or 6.8 h beams with . 990 small end, 2.375 big end. I had planned to use it in the aluminum block, but it makes more sense to put it in the megablock for now as a spare motor. i can end up at -.027 (below) to +. 013 (above) piston to deck hight with a good crank that has rounded leading edges on the counter weights and double keyways.
The down side is the large 2.375 bearings. But i will have to find another set of 440-1 castings to put the megablock back together.