I'm thinking about buying a new rigid frame but don't wanna buy a new front end so I need help determining if my stock front end is a 7/8" or 1". Please any info would be greatly appreciated

 

I found this comment on another forum. I am not certain that it is correct but it may be. There have been discussions of this topic where very knowledgeable guys have been incorrect so best to check around some more ...

HD changed to a 15/16" stem in 1978 and onwards, until the 1" stems for the 39mm forks