Plucked the 8.5 open rear from a friends '72 Skylark the other day for a future build- up. It has a code "LA" stamped on the axle tube, I can't find that code in my '70 Buick literature but another post listed that as a 2.78 in 1966-- same in '72??? (trivial question) I understand this rear will have 28-spline non-C-clip axles (has "B" in the code too) would a carrier from a GM C-clip 8.5 rear end work with the current bolt-in axles??? I'm curious in case I stumble upon a posi carrier in the boneyard. I've had an Olds "12 bolt" posi rear for a long time and it seems to me the axles interchanged with the originals in the 8.2 from the '70 rear end it replaced, but I could be mistaken after 15+ years. I can't remember how many splines an 8.2 axle has. Would the 8.5 corporate axles interchange with my Olds rear or an 8.2??? ou: I guess it would just be nice to know...... I couldn't find any old threads about this, but I did see one in regards to the Olds rear end from Rodger, sounds like changes were made to those mid-year in '70---- I need to get the numbers off mine, I guess...... Sorry about the rambling, I'd probably go with new carrier/gears/axles/bearings in the 8.5 anyway to build a 3.73 the right way, but I like to get answers and opinions to my nagging questions..... Thoughts?????? :Comp:
I have this article on our site. Get the GM 410408 8.5" posi from any 80-87 GM full size wagons. Sell the 12bolt Olds posi you have to an Olds purist. Check out the ads on www.442.com to unload it. If this is for a street car w/no highway cruising, 3.73 is ok. For highway and street, go with 3.08. Original 72 rear will have a 2.56 for a 2bbl car and 2.73 for a 4bbl.
I've seen your article, George-- very helpful, thanks. That was my inspiration for finding a posi in the junkyard, but I would most likely use my 8.5 inch for a strong 3.73 build for some strip action with my BBB car, allowing me to use 28" tall tires and replace the Olds 3.42 rear/26" tire set up I use now. I may sell it some day, but it'll probably find its way under one of my Skylarks (2.56 open rears) for kicks. I also have the 'ON' code 3.64 8.2 Posi in my '70 Stage 1 project car, which will not be a trailer queen when finished so I will need to decide on which to rebuild (8.2 or 8.5) at some point. The 8.2 has been under the car but with cover missing for years ou: o No: So George, the GM C-clip carriers are compatible with a bolt-in axle 8.5 I take it??? Anybody know if the axles will interchange between these three rears???? Rodger???? Thanks for your help guys......
I use the c-clip carries all the time in non-c-clip rears. I think the Olds uses a different axle since I had one fail in my dad's car which has an Olds 12 bolt posi. The Chevy 12 bolt is a 30 spline axle. As for your Stg1 car, you can always grind the "corners" off the center section to make it look like an 8.2 for shows. Otherwise, I would install an 8.5" and not worry about it.
It sounded like you used the c-clip carriers without changes, just wanted to make sure. Rodger's post about the Olds rears I found in a search mentioned changes during the 68-70 span of those rears, due to the bearing/axle scoring issue (like your Dad's?) Now I'm curious which one I have.... I knew a Chev 12 bolt axle wouldn't interchange, but I thought the 8.2 and my Olds rear axles did in 1989 when I made the swap-- Maybe they do on the particular version "O" I have, or my memory is incorrect (very likely) How 'bout the 8.2 and 8.5 bolt-in axles, are they compatible or have you tried this George??? I snagged the 8.5 with the thought of using it as a replacement for the Stage 1 rear as you suggest since it needs so much work, being the cone type..... but I worry about not being able to find any parts for that 'ON' 8.2 further down the road if I wanted the car 100% correct....... I guess I need something to fret about...... Anybody else tried interchanging axles between the type 'O', 8.2 and 8.5???
I was scrap the 8.2 units in the cars I buy so I can not answer your question on interchange from 8.2 to an 8.5 axle shaft. I would replace the 8.2 and store it. When swapping to the 8.5 in your 70, you will have to shorten the driveshaft 1-1.5"
Dan, The '64-67 "B" 8.2 & '64-69 "P" 8.2 10bolts used 28 spline axles, but both used a slightly different spline than '71+ 8.5 28 spline axles. One cannot interchange axles between the two, both due to spline difference, & axle bearing/seal design difference. Type "O" 28 spline axles ('67-70 Olds useage) used same spline as the early 8.2 "B" & "P" 10 bolts. Do not have a '68-69 or '70 Buick 8.2 axle in front of me, but believe I've checked them before, & they also are not the same as the 8.5, spline wise. 28 spline C-clip axles. Not to confuse things, but Chevy used 8.2 c-clip Chevy 10 bolts rears in most '65-'67 Chevelles, '67-69 Camaros, & '68-71 Novas. All these used same shaped 28 spline axle as later corporate 8.5 rears. Rebuilding a '72+ 8.5 "Nova" rearend, & axles are pitted on the bearing lands, one has many yard sources (other than 8.5 X-bodys) for replacement axles. :3gears: Roger
George-- Thanks for the reminder about having to shorten the driveshaft-- I did keep the driveshaft from the '72 coupe the 8.5 came from in case it found its way into a small-block car.....I appreciate your help/opinions. Roger-- Thanks for clearing up the axle interchange issue. I really should have a Hollander to help with questions like that!!! After reading your old post about the "o" axles, I thought maybe the "o" piece I have had a bearing/seal design compatible with the '70 "b" type 8.2, like I mentioned before I seem to remember mixing/matching the axles with the best bearings when I swapped those two rears in 1988-89...... I'll remember to label 8.5 axles now. Thanks for sharing your knowledge/experience in this field with us, Rodger. MANY of us benefit from reading your posts. Same goes for you, George. Thanks a ton guys.........
Thanks, Pete--- I still haven't figured the ratio yet, I'm curious to confirm it when I get some time.....
Thanks for confirming the ratio, guys-- good enough for me, its too cold out to even look at it now.......
