Originally posted by unioncreek
Check the rear flange on the crank first then measure the stroke through a spark plug hole. 360 is 4.5", 390 is 4.78".


Say WHAT?????? You'd better check again. a 360 and 352 had a "3.50" stroke and a 390 has a 3.78 stroke. I can't for the life of me figure out where you got the 4.5 and 4.78.