I am looking into swapping out the stock rear on my 69 skylark, as I am in the works of looking for and hopefully finding a decent 455 and a TH400. I've found a 8.2 10 bolt posi unit out of a caprice ( I've heard they switch up real easy) It has 3.90 gears so a few questions. 1-What kind of street cruising would 3:90 gears give me, pros vs cons? 2-What does BOP mean? 3-Is it possible to replace the 3:90 gears with say factory original ratio gears like 3:64:1 or 3:42:1? Are they even available? 4-How difficult would a complete rear swap out be? 5-What kind of rear should I be looking for? 6- WHat kind of axle should I be looking for and how difficult would it be in terms or clearence issues, angle changes etc..? Anyone with any specifics please help me out, if anyone has pictures of anything that might help please send em my way on the thread or email me at dip815@yahoo.com Thanks.
wow rear swap wow... THINGS HAVE CHANGED IN 6 YEARS...LOL THIS INFO IS WRONG FROM ME! Ok well I will try this one...The gears will fit...It is not just as easy as bolt and go though. The posi from a caprice is 28 spline but has a different degree spline angle and design . This would make the BUICK OLDS PONTIAC (BOP) axles fit kind of loosely in the posi. You can use 71 72 axles which will have the same axle spline as the chevy axle spline of the 8.2 c-clip type rears. Street cruising...Well alot would depend on the diameter of your tires over all height 26 27 28 29 30 inch tires...etc. The bigger (taller ) The tire the more streetable the gears will feel. Again it will also depend on your tolerence for noise and rpm reving. If you like tooling around town and never hit the freeway they will probably suite you fine. If you like cruising to different city and shows in your state...Maybe NOT. Gear availability... 3.64 I think are not available nor 3.42 for BOP rears. You might find a NOS new old stock part in some old guy shop ...but you might end up spending an arm and a leg to get it. In chevy c-clip gears 3.08 3.36 3.55 and up are all available. BOP gears 3.55 3.90 and 4.56 are your aftermarket choices. CORRECTIONS- IMPALA AXLE WILL NOT FIT AND WILL NEED TONS OF MODS TO FIT TOO WIDE UPPER CONTROL ARMS WRONG SHOCK MOUNTS ON THE WRONG SIDE OF THE AXLE TUBE...AND MORE. THE 8.5 COULD WORK IN THE 1968 69 70 HOUSING BUT WILL ONLY FIT THE 2.56, 2.73, 2.93 RATIO WITH THE 3 SERIES 8.5 CARRIER. but THE BIG FACTOR IS THE DRIVER SIDE HUB WILL NEED A SHIMMED UP BUSHING TO INCREASE THE BEARING HUB DIAMETER. BUT IT CAN BE DONE... Most everyone on the sight seems to like the 71 72 Skylark and cutlas rears they use the stronger 10 bolt 8.5 posi units with the normal 28 spline axles that bolt in. Gears are readily available from junk yards to mail order to speed shops and very good prices ...Posi tractions are still very findable at local yards too. These rears can also be up graded to 30 spline and even 33 spline. spooled power traxed what ever. I can supply you with 8.2 posis and try to get you prices on gears...(probably not as low as others because Richmond has a market on the BOP gears. Posi 8.2 BOP I can get Auburns for 399.99. NEW 3 series Hope this helps in your quest for the ultimate rear for your ride. Jim
'68-70 BUICK 8.2 3.42 or 3.64 ratio gears are next to impossible to find used, & that's what one is going to be stuck with looking for, if looking for low ratio BUICK 8.2 gears. One must also remember the 68-70 BUICK gears are not the same as '64-67 (used through '69 in Pontiacs) BOP. The used 8.2 Chevy posi carrier is another nightmare, if trying to use in a '68-70 BUICK 8.2 rear. Not that strong, & dimensionally different than the '68-70 BUICK posi carriers. All in all, the 8.5 A-body swap is the way to go. :3gears: Roger
I appreciate the help guys. I had no idea the difficulty involved with the caprice posi. I had read its "a perfect fit, easy bolt on" what a load of garbage that is huh. Anyways, I guess ill have to settle for a 71-72 rear set up, best bet try finding a whole axle drum to drum? or just going individual on the pieces and work it that way?
Get the 71-2 Skylark/Cutlass 8.5" rear. Saves you money and a lot of headaches. You should be able to get a complete non-posi rear core for $100-150.
Rear End Available dip815, I have a drum to drum rear end assembly, with 8.2 Richmond 3.90 gears, positraction unit, and boxed upper control arms that will fit your "A" body. I have 3 years use on it since I purchased it "rebuilt", and it is quiet, dry, and ran fine till I replaced it last week. I had it behind a strong 400 engine, 12.93 at 105 mph, and never worried. I had GM Jim build me a new unit (very nice work), as I just added quite a bit to the engine, and didn't want to worry about the diff. I'll take $400.00 for the unit, loaded in Ohio. I could also bring it to Norwalk or Salem Buick Drags. Michael Dyer Clinton, Ohio www.67gs400.com
Michael, is that 8.2 out of a 67 GS? If so, I"ve had a couple posi rears out of 67 GS's. I was told that it is actually a pontiac rearend. Instead of a cross pin and two spider gears it has an "X" shaped pin and four spider gears. They are amazingly strong. I was getting 1.48 60' times on my little old 8.2" posi. I think $400 is a very good price, dip815 should jump on it, if not I guess he's a dip.
Michael, I appreciate the offer and wish I could do it. I'm just 22 years old, most of the money I make goes towards the car. But I just spent the last amount I had saved on a completely rust free 69 GS hood with the inserts so I'm tapped out. If in a couple of weeks you still have the unit, I will try to get ahold of you and we will work something out. Thanks
Rear End 4 guys have jumped on this, Peter Brown, Dennis Wheeler, and 2 others in that order. It's sold, the question is to whom. Peter is measuring his to see if it fits, if he passes it goes to Dennis, and so on. Michael Dyer Clinton, OH www.67gs400.com
Re: Rear End Available Dude,this thread is from 2006,its 6 years old,I'm sure the thing is gone by now. It looks like your new,welcome to V8Buick.com. If your looking for a part,try posting on parts wanted,if some one has what your looking for they will let you know.:TU:
LOL,settle for a 71 or 72?find a 71 or 72 corporate rear from another a body,if u find one from a cutlss wagon you also get bigger brakes,parts are readally available,you can use the posi unit from an a body or full size you will have bolt in axles on bop rears and c clips on chev,u can use the c clip posi,just use o type axles and toss the clips,judge for yourself,the 8.5 corporate rear has bigger axles than a 12 bolt,8.5 rear has 7/16 ring gear bolts,12 bolt has 3/8 bolts,front pinion bearing is larger on a 12 bolt,yippi,i ran one of thes rears in a 67gs for over 10 yrs and i thinkk its still goin
