Cold Case radiator # mop 755k

here is the measurements for a 70-up pulley set up.


6 9/16 on the crank and 6 7/8 on the water pump.



View attachment 1715499182

View attachment 1715499183

That top set is about 12% over. That is much better than what the OP has. I didn’t see what he actually has but he said it’s underdriven.