Can anyone identify my rear differential? 8 3/4 but wrong markings???

So an early ford 9 instead I guess.
I don't think so. Most of the "early" Ford 9's had "dimples" on each side of the pumpkin, while this one is smooth. Easiest way to tell if it's a 9" is to measure the spring perches, as they were a "standard" dimension, if memory serves, but it still doesn't look right to me, so.....

I did some digging here at work during my lunch, and I think what you is an 8-3/4" rear alright....but a Ford 8.75, not a Mopar.

Google "8.75 Ford rear" and you'll see what I mean.

And for your sake I hope I'm wrong, as I understand that finding parts for these can be a PITA.