Sometimes I feel like I am going 1 step forward and 2 steps back.

Tried to put in what I thought was the correct distributor for my 383, that I bought a long time (15 years) ago, based on the number on the housing. Should be 2875358. But when I put in the motor it wont go in all the way. Oil pump shaft is seated down, btw.

Searched and found this previous link: https://board.moparts.org/ubbthreads/ubbthreads.php/topics/1904196/re-distributor-shaft-lengths.html
When they say "Measured from mounting surface to end of distributor shaft." this means the flange/base that seats in the block top surface? Thats what I thought.

I dug out an old 440 RB distributor I had laying around and sure looks the same to me. So I guess I have a rebuilt that someone put a 440 shaft in? Well that sucks. Guess I got to find a 383 donor and swap.