A rear has become availability for sale in my neighborhood. Owner bought it a few yrs ago at the GS Nationals and never got around to installing it.’He was told it is a 2.73 ratio posi ;stored indoors. It is literally less than 2 miles from house . I have 2 questions 1) can the ratio be lowered to the 3.08-3.23 range ? The rear - through pictures looks to be an 8.2 BOP drum to drum type . Question 2 is where on the rear is the stamping located that denotes build date ratio, etc located ? I their I remember it’s on the passenger side axel tube on the top what letters should I be on the look out for ? I know gears for the 8.2 are scarce but the price of rear is CHEAP , Thanks in advance guys.
It depends on which 8.2. There was the BOP 64-67 8.2, of which gears are easy to get. Then there is the 68-70 Buick only rear. Fabcraft is the only one who has made gears for them in the past, just 3.42 and 3.64. Not sure whether there are any left or they intend to make another run. http://www.jdrace.com/content/diff_id/10bBOP_Early.php http://www.jdrace.com/content/diff_id/10bBOP_Buick.php
Thanks for the links, I believe the rear is the 68-70 variety. At least now I can trust but verify with confidence.
You will have a harder time finding gears for that rear. Like I said, last I heard, only 3.42 and 3.64 reproduction Ring and Pinion was available from Fabcraft, and TA Performance. That rear is more expensive to build.
Thank you for good explanation and for sharing such good links, I am enjoying in this forum because of expert opinions.
Early 64-67 will be 2.78 anyway...they did not have the 2.73 till 1968...that was till 70 then it wen tot 8.5 in 71 72 - 1973- 77 2.73 also. Difference is the rear end housing. casting on a 1968 - 1970 will end in the last 3 digits 700 or 724. THAT rear i try to get people to call a 8.25 rear. Very BUICK rear carrier bearings are different sizes.,..Pinion bearing Huge 1.875 diameter. Just all on its own for rear end parts. NOT to say it is a bad rear by any means...Solid for sure...Just hard to build at this time with lack of ring and pinion selection in the aftermarket (Fabcraft Metal works.) Jim JD
Thank Jm for the detailed info ; it seemed but a few yrs ago posi 8.2 & 8.5’s were relatively easy to find used in good condition for not a lot of $$
A fiend called Fabcraft within the last couple of months. They have no date set for once again reproducing 3.42 and 3.64 gear sets.
Hard to make money with out MONEY....lol. I think there are only 3-4 gear sets in stock that they custom make. The BOP gears you can get from anywhere... (64-67) Rebuild kits the bearings are available if you know the part numbers from any store. WE just need the special stuff they only put out...That is the 9.3 Pontiac Olds gears. 3.42 3.90 etc. Those are 2 most popular choices in my builds.
I decided before buying or even looking to upgrade my rear to verify with certainty what is in my vehicle now . The original owner I purchased it from was getting up there in years and was only marginally helpful in so far as components that were changed. He did have mostly every receipt in 40+ yrs he put into the car. He told me there was a 2.56 non-posi in the car from the factory . Driving the car after going through it showed that 55-60 mph was approx 1900rpm This seemed in the ballpark for 2.56. I’m wondering if there might be 2.73 ratio in car after speaking to 2 people that owned 1968 Skylark Custom’s . What I’m hearing is the350-2 bbl’s got the 2.56 and the 350 -4bbl’s got 2.73 rears . I was under the car for a few hrs today looking for the axel codes o the pass side axel tube and no luck. Degreaser , wire wheels , and finally 0000 steel wool got me a clean tube with no markings. I’m sure it’s an 8,2 ( 8.25 ) on posi by that’s it . I did find some #’s on the drivers side bottom of the housing that might be casting #’s . I have some pictures of my cleaned axel tube & the number’s I did find. I’m looking at a 2.73 posi but if I’m running 2.73 gears anyway I’ll keep looking Thanks again for your opinions & insights
Check the driver side axle tube facing the ground. It is a Buick rear 1968 - 1969 Between the spring perch and cast center facing the ground. ...Look there.
