New Slant

I just got a reman 225 slant for my 71 Swinger. They told me that there was a specific crank measurement that they looked up to find the motor for me. they said the right measurement for that year was 1.8" or something like that. Does this refer to the crank hub? He is certain this is the right version and i have not put the motor in. If its not the right one, what do i need to change in the trans to work, given that it has anything to do with it? Thanks.