I have a '61 Merc 500 and it runs great but unfortunately my lower end is messed up and also a short shaft wich is wrong for my boat. i also have a '64 Merc 1000 long shaft wich fits my boat nice but doesnt run... i was wondering if anyone knows if i would be able to swap the lower ends on these and it would work? all of the bolts to the motor are in the same places and the dimensions are right, the only problem i can think of off hand is different size crankshafts in the units... any help with this would be appreciated, im going to try to take them apart and see for myself asap (hopefully in a day or two), but i was just seeing if anyone could let me know what kind problems i should be ready for - thanks.