1977-78 GM Chassis Class A Motorhome with 454 and 4.56 rear end.

Need ID of rear diff. I can find no numbers/stampings to ID the rear end.

I count 14 bolt. Could be a 10.5" corporate or an 11" Dana? Any other idea'*? Does the option code mean anything?

My initial guess is it'* a corp 14, I have been a truck mechanic for 15 years or so now. Can ya take a pic of the end of the axle shaft like as if you were looking at the tire? Also, if you take the axle shaft out if I remember correctly the dana/gm diff will have different axle nuts if u get me that info I can tell ya for sure.