In my 66 Skylark i have the original 8.2" open 10 bolt with highway gears. I will be running a '73 455 that I was told from TA that it'll be a 500+ HP build when i'm done. I found a 69 Olds type O 12 bolt open rear end for sale somewhat locally and I was wondering if it will be a good upgrade from the 8.2? The guy wants $650 for the rear end, although I haven't bartered with him yet because it's a 4 hr round trip to get it. I'm waiting for more info on it like ratio, condition, etc. I plan on running a posi unit. Should i save up for a different rear or would this be a good one to build for street and occasional strip? Thanks guys
I wouldnt build the olds rear, and 650 is WAY to much for it no matter what gears it has. The olds rear will still be an 8.2 when youre done, and kind of an oddball for parts too. Contact JD Race, Brian Trick or Everyday Performance to see if someone can build you a 71-72 Buick/Olds 8.5 rear for what youre about to spend on that Olds 8.2....
Your 66 rear if orginal, is narrower than than the later cars but a little over an inch if I recall. Just something to keep in mind
Unless you plan on racing with slicks, I would just build your current rear. Gears and Posi are readily available out of the Jegs/Sumitt catalog. The Olds is an oddball rear, 12 bolt with 10 bolt internals, not a bad rear though.
A 12-bolt O-axle can handle the power. However,I would NOT pay $650.00 for one that wasn’t a posi. A typical 2:56/2:78 non-posi is a $150.00 core. If it has 3:23’s,it’s worth a little more because it has a desirable gear,but still nowhere near $650.00. I would either build your existing rear,or build a 71-72 8.5” 10-bolt.
Your 66 has bolt in springs? To go to a 8.5 you will need different wheels (offset), different springs at a minimum. I'd build up your existing rear, it can take the BBB you are building. Send it to one of the folks Rhett mentioned.
Thanks for the input. I've been looking at BOP style 12 bolt posi rears on Feebay, but they are $1500-$4000 and most are local pick up only. I would like atleast an 8.5 posi with 3.42 or 3.55 gears. I'm in Utah so maybe I will wait to see what pops up locally. I'm in no rush.
I've got a 71 Buick 8.5 10 bolt 3.08posi in my 66 Skylark w/455. I'm running the standard 15x7 Buick rally wheel 235/60-15 BFG Rad TA on it, no problems. You will need a different length driveshaft if you put the 8.5 in. Bought the 8.5 open rearend for $100, then bought full rebuild kit, used 3.08 gears, and rebuilt posi unit from Monzaz(JDRace) of the board here. Put it together myself and probably have as much in it as that used Olds rear you were looking at.
You will not need different springs. Yes,your current axle may have the style that bolt to the flat plate,but the ends of those springs are shaped the same as the later ones,and fit over the perch. Your 66 rear should be the same width as the 71-72. BOP only used the narrower rear in 64-65. There might be some early 66’s with them. Chevy kept the narrow one for 64-67. When swapping from the BOP 8.2” to the 71-72 8.5”,you will need to shorten your driveshaft about 3/4”. The driveshaft is your only modification. It still uses the same 3R U-joint.
Thanks for clearing this up I though buick kept the narroworld housing till 68 as well, love this place learn something new every day
What were the biggest changes to the GS rear ends over the standard Skylark? Axle shaft size and bearings?
I don't think there were any changes other than the Posi carrier and gears. Axles and bearings were the same. I could be wrong. I'm sure BrianTrick or Monzaz can answer definitively. All the Buick rears were bolt in axle and used the big u joint unlike the 12 bolt Chevys.
Yes That is all - and in 1970 there was NO Difference at all - They all used the oiled Set 9 bearing type.
Axles and bearings were not the same as regular Skylark. The 65 GS and Sportwagon used a wheel bearing with a larger OD. The axle tubes were larger near the brakes to accommodate the larger bearing. Bearing was a RW507A Starting in 1966, The GS and Sportwagon also went to a larger diameter axle, requiring a change in the bearing to a RW507G. this was used thru 1968. I lost track of the changes after that..... I don't have any of those 'new' GS's.
Thanks for clearing that up - This board is great for that. Jim F - How close to the fender is the tire? Could you go with a larger tire?
If I were to do it again I would spend the money on a 9" because of more gear selection. But I had a chevelle 8.2 upgraded with 9" ends, narrowed an inch, and moser axles, 3.73 gears. theres a guy with a 496 nova that did this and his car runs 8.90's and its holding.
Hummmm a CHEVY 8.2 running 8.90....I would really like to see that...The car must be a engine only no body frame etc. 8.2 CHEVY is weaker than the 7.5 10 bolt in the pinion area... Take some pictures of the rear under that car the next time you see it run 8.90. lol. Jim There is not even a spool for that rear??? They only came in 28 spline ... soooo. MAny it is a 8.5 and looks like a Chevy rear because they take the same rear cover and are interchangeable... Could have put a Chevy cover with the eyebrow on the 8.5 rear...lol.