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I bought this W27 cover thinking that it would fit my 71 ten bolt cover rear end. Does it? I prefer to know before I take the old cover off. The gasket laying on it is incorrect. It's a Fel-Pro RDS30031 and I believe it's correct for a later 70's big car. If it does fit what's the correct gasket number? I've searched a bunch and can't seem to get a straight answer. (I apologize that one pic is rotated 90 degrees in relation to the other)
Last edited by allyolds68; Sep 12, 2017 at 10:06 AM.
Are you sure your axle is an 8.5? It kind of looks like an 8.2.
The cover looks like an 8.2 but the ears at the bottom look like an 8.5.
I posted it here after Facebook because of all the senseless comments about making a gasket for it and such. As I posted on FB, I've put a bunch of effort in to finding out what gasket fits (and honestly, what rear end it is too). I bought it from Brian Trick about 8 years ago and he told me it was from a 71 Olds. When you plug a 71 Olds 442 into most auto parts sites you don't get much of anything for a factory 10 bolt gasket and none have the "scalloped" edges like my cover does. I'm beginning to think the steel cover that's on it is from an earlier rear. From what most are saying (except that one guy on FB who said it wouldn't fit) is that it will fit. One guy PM'd me and and said a lot of the repro 10 bolt covers don't fit right and the upper hole has to be elongated.
The cover was a good deal so I don't really care if I have to tweak it a little to fit
When you plug a 71 Olds 442 into most auto parts sites you don't get much of anything for a factory 10 bolt gasket and none have the "scalloped" edges like my cover does.
Interestingly, RockAuto has it wrong if you search for a 1971, but shows the correct 8.5" gasket if you search for a 1972.
I've put a bunch of effort in to finding out what gasket fits (and honestly, what rear end it is too). I bought it from Brian Trick about 8 years ago and he told me it was from a 71 Olds.
If Brian told you that, then believe him.
Also, don't try to ID the rear based on the cover. Look at the side of the center section to see if there are two parallel ribs, and look at the forward face where the tubes insert and there should be block O.
I agree that Brian would know what it was. But here's an observation to share that may or may not be right. And... if its not here's my chance to have someone correct me! The 1964-67 8.2 and the Type O will have a two letter code for the ratio, limited slip, etc. But I've looked at several 71-72 corporate rear ends and found more digits stamped into the housing. Here's a picture of what I'm describing. Does your housing have something like this or just the two digit code?
And one more thing, I just remembered that the 1964-66 8.2 with a bolt on spring used a different bracket for the brake line. It has a notch in the inspection cover with an L shaped bracket for the brake line. The corporate 8.5 had a hole cast into the pumpkin for the brake line attachment. Here's a picture of that. I had to use the flash for this picture... done for the night!
I took this side pic this morning but in the meantime Brian trick replied to my FB post with this:
There were two different castings of the 8.5" 10-bolt,for 71-72. The Lansing-built cars had what I call the "O"-casting. It has a large "O" on each side of the pumpkin,between the ribs.This has a round cover,with an eyebrow running from 12:00 to 3:00. The other casting is what I call the "A" castings.This casting came under all 71-72 Cutlass/442's that were not built in Lansing,and all 71-72 Buick Skylark/GS. This has a large "A" on the top of the pumpkin,and also an "A" on each side,between the ribs. This casting has the cover that looks like a BOP 8.2" cover,with the notches at 9:00 and 3:00,but it is different. The bolt spacing is taller.
The 8.5" 10-bolt W27 covers will fit both castings,and both castings have bolt-in axles,no c-clips.
I still haven't been able to really crawl under and see if there are any numbers on it. If you look closely at this picture you can just see the "A" on the front of the casting
Mike,
Looking at your picture, I'm comparing it to my car. I also have an OEM sway bar. I boxed in the original rear control arms, but my sway bar ends up touching the bottom of the differential. Any idea what might cause this? I'm kind of stumped. Shims are 2 on each side which centers the bar under the differential, but it's touching now.
Here's a pic that shows the "O" on both axle extensions. I took this when I upgraded to 3.42's.
Second pic shows the W-27 cover (although never offered on 72 models) does add extra capacity to the differential and somewhat better cooling with those fins. I added it because it's cool. Painted the pumpkin silver because it also looks nicer that way.
Lansing axle. Code SA 101. Matches the build date of the car. Cutlass S 2.73:1 ordinal date 101 = April 10. That was the day my car received it's chassis and rolled off the line at Lansing.
Bolts replaced with proper ones before install and does hold more gear oil.
Ok from the pictures in the first post -
That is a Buick 10 bolt 8.5 rear. They were shared in the Olds cars also... You know how it goes in the plants ... stuff it in and keep it moving.
Next picture. The w27 8.5 and the gasket.
It appears you bought a PONTIAC full size 8.875 cover gasket...Which has the same appearing cover from a far but when you put a full size Pontiac 8.875 cover next to a 8.2 Pontiac cover the only thing that is the same is the general shape and cut outs. This is because the Pontiac is really a 12 bolt ring gear and larger diameter ring 8.875.
The 8.5 Buick and the 8.2 Pontiac again appear to be the same size shape etc. BUT again are different. the bolt pattern of the holes are slightly different and as another poster mention the 8.2 cover will ALWAYS have the cut slot for the brake line L bracket while the 8.5 will have little round bumps at the top and bottom of the 12 and 6 o'clock positions and the cast in boss drilled and taped the hold the rubber brake like to the chassis connection.
NOTE the old Buick 8.5 scalloped cover gasket has been discontinued and they only make the round one now. So if you do not like the extra gasket material hanging out of the 3 and 9 o'clock position just trim to fit.
Order a 8.5 gasket for a 1975 camaro and you will be good or a 1980 10 bolt truck will work also.
If you do find a NOS 8.5 scallop gasket...well that is cool too.
10 bolt 8.2 Pontiac 64-67 cover WILL NOT FIT! Bolt pattern is different as i stated earlier.
