I have a 742 case that I thought came out of a 1967 New Yorker. Maybe it came from something else. The pinion seal was bad so I looked up 1967 NYer and it gave me part number 8515N, but when that arrived it is too small. I tried to look it up a couple of different ways but having trouble finding a resource that tells me the application AND the measurements.

8515N has an OD of approx 2-7/8"

from measuring the opening of the case, I think I need a seal with an OD of approx 3-1/8"


Anyone got the info or can point me in the right direction?

Went through the same issue myself. Many of the websites/catalogues are wrong. Mancini's or O'Riely's has the correct part numbers. If I remember there were three different seal numbers that matched to a 8-3/4 rear. I believe O'Riely's even had the dimensions of the seal to double check.

Good Luck,

Rockauto lists them by casting number, the 8515N you have is for a 741 casting. 7216 is for a 742 casting

Dr. Diff has what you need and he's a member here. Nice dude.

http://www.doctordiff.com/8-3-4-pinion-seal.html