As some of you may already know I'm slowwwwly trying to restore my 68 SS. My car has a 12 bolt rear stamped CI which I believe is a 3.73 geared posi rear. I Spun the tires and that seams to be right, drive shaft spins about 3 & 3/4 times for one turn of the tires. Somewhere along its history someone put a Chrome then painted rear end cover, which I thougt was original but probably is not. After inspecting the inside of the cover a groove has been cut by the ring gear , which can't be normal. I'm not sure if these are the original ring & pinion or just a poor quality cover. I got some part #'s from the pinion gear which look like 11-41-4317 67, also the ring & pinion have a painted A45 on them. Do any of you what this represents and would a GM restoration Rear end cover fit correctly, not hit the ring gear.

Thanks any help or advise would be appreciated

Not sure on the numbers, but puchased a GM restoration cover and it fit great when I rebuilt my rear end. If you look in my signature you will see pictures of it under differential.

I've seen several of the cheap chrome covers that rub the gear. Most of the time you will gatch it as soon as you bolt it up because it will lock up the rear end. Someone must have started driving yours as soon as they got it on. Use the Delco cover.

As some of you may already know I'm slowwwwly trying to restore my 68 SS. My car has a 12 bolt rear stamped CI which I believe is a 3.73 geared posi rear. I Spun the tires and that seams to be right, drive shaft spins about 3 & 3/4 times for one turn of the tires. Somewhere along its history someone put a Chrome then painted rear end cover, which I thougt was original but probably is not. After inspecting the inside of the cover a groove has been cut by the ring gear , which can't be normal. I'm not sure if these are the original ring & pinion or just a poor quality cover. I got some part #'s from the pinion gear which look like 11-41-4317 67, also the ring & pinion have a painted A45 on them. Do any of you what this represents and would a GM restoration Rear end cover fit correctly, not hit the ring gear.

Thanks any help or advise would be appreciated
If you want to stay original go with the GM restoration diff cover. Last gear oil change i installed a heavy duty cast aluminum 12 bolt cover that has plugs for adding and draining gear oil, drain plug magnetized. It also has studs for bearing cap support. Spendy, but worth it next gear oil change. Purchased mine thru Summit