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#1
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Rear diff. ID
Can anyone tell me what diff. this is? GM 67 and up 10 bolt 8.5? Its in a 66 GTO I picked up.
thanks |
#2
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That would be my 1st guess, as it is designed for a A-Body vehicle vs a leaf spring car and for sure not a typical Pontiac 10 bolt configuration.
The 8.5 rear axle seems to be a lot better rear axle vs the old 10 bolt Pontiac A-Body parts. Tom V.
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"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
#3
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On front right hand axle tube, viewed from rear,should be a code. Usually 2 letters.
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#4
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I'm pretty sure that's a 8.2 Chevy "C" clip rear.
__________________
“Nothing in the world can take the place of persistence. Talent will not; nothing is more common than unsuccessful men with talent. Genius will not; unrewarded genius is almost a proverb. Education will not; the world is full of educated derelicts. Persistence and determination alone are omnipotent. The slogan Press On! has solved and always will solve the problems of the human race.” ― Calvin Coolidge |
#5
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I'll be taking it out in a few days and take a better look for any markings on it.
I didn't see any that matched it online figured somebody would know. |
#6
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looks like an 8.2 to me
__________________
************************************* 1968 Lemans. 37,000 original miles. GTO clone. 462ci/KRE 290 heads. UltraDyne 280/288 Solid/850 Qjet by Cliff/Performer RPM/TSP 9.5" in TH400/8.5" 3.42 gears/3950# Race weight/12.58@106 at Bandimere speedway high altitude |
#7
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The rear cover does look like a Chevy diff cover.
Without the code though it is a 50/50 on being a 8.2 or 8.5 10 bolt rear cause I know little about 10 bolt chevy rears. The only 12 bolt A-Body rear did not last long in my GTO. Post up the code. Tom V.
__________________
"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
#8
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I don't think the 8.5" GM came out until 1971.
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1967 Firechicken, 499", Edl heads, 262/266@0.050" duration and 0.627"/0.643 lift SR cam, 3.90 gear, 28" tire, 3550#. 10.01@134.3 mph with a 1.45 60'. Still WAY under the rollbar rule. |
#9
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I would agree with that but it could be installed in any 1964-1972 A-Body vehicle.
Tom V.
__________________
"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
#10
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Looks like 8.2" Chevy to me. The 8.5" GM rear has square lugs at the 5:00 and 7:00 location on the bottom of the housing that run parallel to the ground
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62' Lemans, Nostalgia Super Stock, 541 CI, IA2 block, billet 4.5" crank, Ross, Wide port Edelbrocks, Gustram intake, 2 4150 style BLP carbs, 2.10 Turbo 400, 9" w/4:30 gears, 8.76 @153, 3100lbs |
#11
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Great, Gary H. I will remember that tip.
Tom V.
__________________
"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
#12
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Thanks guys I just couldn’t find that cover online anywhere.
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#13
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This is a ‘71 Cutlass 8.5 that I own. ID’ed by Jim Mitschke at JD race. Looks close, if not identical.
Another good identifier is to look at u-joint retention. 8.2 usually have u bolts holding them in, the 8.5 have straps.
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71' GTO -original 400/4-speed/3.23 posi 13.95 @ 102.1 on street tires @ 4055lbs. ‘63 LeMans- ‘69 400 w/ original transaxle. 2.69 gears. |
#14
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facts...
-there were a little over ONE MILLION '71-72 8.5 A-body rears installed in 71 & 72 GM divisions cars.
-3 different versions of the 71-72 8.5 A-body rear were built. The differences are due to the center housing design, & whether the housing ends accepted A9 or A10 axle bearings. - one thing ive noted many times: It's never smart to try & identify a housing by poorly written ID Guides & generalities. How many folks use the term "BOP 8.2"? No such thing, just a long time generalization. From decades of hands on experience, there were Early Buick 8.2's, Early Pontiac 8.2's, LATE Buick 8.2's ('68-70), & LATE Pontiac 8.2's. Bunch of differences over the years. The above pictured rear is indeed an 8.5 A-body rear. Ive posted a pic of that particular style housing on here before & on BuickV8.com when I used to have time to post on that site. In my housing racks have several of that particular style 8.5 A-body housing (only accepts a round cover). Began building up the '71-72 8.5 A-body rears up in the early 90's, while not as common as the style of 8.5 A-body housing that accepts the scalloped style 8.5 cover, have built up over 3 dozen of the style with the round cover.
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Buzzards gotta eat... same as worms. Last edited by 'ol Pinion head; 07-29-2020 at 09:35 PM. |
#15
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I didn’t notice the difference in the straps there was no driveshaft but it looks like a strap setup not u bolts. I have a 66 10 bolt 3.55 with an Eaton posi
for it but want to run a taller gear a friend has a 66 12 bolt with 3.08’s. I was considering But maybe this will work. I’ll try to get to it tomorrow. |
#16
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Quote:
Thanks OPH for the informative post. Tom V.
__________________
"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
#17
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Well pulled it looks like 2.73's 41/15 on ring gear. Not sure how that went with the M20 2.52 first gear, sounds gd for the interstate though.
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#18
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2.73 was most common ratio on that particular 8.5 A-body rear.
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Buzzards gotta eat... same as worms. |
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