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#1
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12 bolt yoke tech help needed.
So I have a 1970 Pontiac GTO with a 12 bolt rear end. I am removing a 4 series carrier and replacing it with a 3 series carrier. Rumor has it the 3 series came out of a 1968 Chevrolet Chevelle. So I'm having to use the Chevy pinion/yoke and of course the Pontiac drive shaft. I am struggling with tracking down an adaptable U-Joint and even more importantly a useable U--Joint part number? I've gone thru a couple of MOOG U-Joints that have just missed the mark, your help would be greatly appreciated. Thanks
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#2
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I take it your GTO didn't have a 12 bolt in it originally?
These I think are the U-joints that should work? (been a very long time since I did this) Napa PN 372 Precision 372 Neapco 3-3130 Spicer/Dana 5-3022X I used the 5-3022X I think. But probably easier to take one in and compare.
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John Wallace - johnta1 Pontiac Power RULES !!! www.wallaceracing.com Winner of Top Class at Pontiac Nationals, 2004 Cordova Winner of Quick 16 At Ames 2004 Pontiac Tripower Nats KRE's MR-1 - 1st 5 second Pontiac block ever! "Every man has a right to his own opinion, but no man has a right to be wrong in his facts." "People demand freedom of speech to make up for the freedom of thought which they avoid." – Socrates |
#3
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No I'm pretty sure it did come with a 12 bolt. This was a Canadian built car and from what I can gather these had Chevy 123 bolts installed from the factory?
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#4
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Thank you John, that part number matched all the measurements that I need . Damn that was fast. Thank you again.
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#5
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The Pontiac 3R 12 bolt yoke should work, all 12 bolt pinions had the same spline count regardless of Pontiac/Chevy and U-join difference.
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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. |
#6
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For anyone interested the MOOG part number is 372.
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#7
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Quote:
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#8
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Your car only came with a 12 bolt if it is a 455 car. Take pictures of the casting number on the rear and the 3 series carrier, what is the code on the axle tube? The carriers have nothing to do with the pinion yoke.
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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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Chevy used a smaller u-joint than Pontiac, and even though both are the c-clip rears, yoke is different. As mentioned, carriers have nothing to do with the yoke. You can't mix 10 bolt BOP, 12-bolt Olds or chevy 12-bolt yokes, none will interchange. To use the Pontiac driveshaft you must use the Pontiac 12-bolt yoke which are exceedingly hard to find. There is a u-joint available to mix the chevy yoke with the Pontiac driveshaft. Your pictured code appears to be a chevy c-clip rear code.
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#10
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If I remember correctly lakewood was the one I used a long time ago or it might be Moroso. Each joint has a different yoke size. Hope that help you some. If not try posting in the race section someone they may know.
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#11
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Looks like you have the narrower 12 bolt from 65 to 67 chevelle maybe. 68 to 72 12 bolts are wider so the axles would be longer. Just use your shorter axles. Your carrier will work fine though and you need the 1310 to 3r adapter u-joints from post 2.
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#12
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The 3R (S44) pinion yokes for Chevy 12-bolt are indeed very scarce. I couldn't find a single one, new or used, online. There are 3 common u-joint size pinion yokes readily available for the 12-bolt. 1310, 1330, and 1350. You apparently have the 1310 which is the smallest of the three. Big block Chevy's usually got the 1330 pinion yoke. The 1330 u-joint is very close in size and strength to the 3R (S44) that Pontiac used. If you need to replace your yoke while rebuilding the differential (old one grooved?), you'd might as well upgrade to a 1330 yoke as there's virtually no price difference. The hybrid u-joint you need for that is Spicer 5-793X. 1350 are very commonly used for racing, but would be overkill for street use.
Here's a 1330 yoke that uses U-bolts. There are also versions that use straps and bolts if that's your preference. https://www.dennysdriveshaft.com/p37...y_12_bolt.html
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Hoping to finish a project while I'm still able to push the clutch in.... 1963 Tempest Convertible (195-1bbl, 3-speed transaxle. 428 RAIV, 5-speed, IRS planned) Pictures |
#13
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I joint
If it’s any help, 40ish years ago, I used Borg Warner part# 114-9hd to use a 68 Camaro 12 bolt in my 68 Firebird 4spd.
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#14
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The 3R 12 bolt pinion flange really isn't worth chasing, unless you have are involved in a very high point Concours restoration on factory 455 / 455 HO A-body car, and even then, most well versed national show judges wouldnt know the appearance of a factory 12bolt 3R pinion flange from an aftermarket cast steel Spicer 1330 piece. Would agree with tekuhn, the u-bolt style spicer 1330 12 bolt pinion flange is the way to go. Ignore the Parts Place listings & other sellers who are selling a spicer 1330 pinion flange with bolts & straps for the '70-72 455 application 12 bolt, that's incorrect.
Rebuild tips for those with a factory 12bolt with factory installed pinion flange. During a build with a factory 3R 12 bolt pinion flange, one has to be very very careful reinstalling a factory flange, as if there is any "rock" of the pinion flange holding tool when bolted up (Kent Moore or aftermarket slotted style), one or two of the corners of the 3R 12 bolt flange can chip out, ruining the pinion flange flange. When rebuilding McKinnon 12 bolt rears which came with a 3R pinion flange, I go through the last phases of the build with a common 1310 12 bolt pinion flange. This means using the 1310 pinion flange to compress the new crush sleeve to "near" correct final dimension. Only after the differential has patterned out, do I use the 1310 flange to compress the crush sleeve. Then, I install the correct pinion seal (McKinnon 12 bolt & 3R pinion flange used a different pinion seal), & oh so carefully tighten the factory 3R 12 bolt pinion flange using a pinion flange holding tool of my own design, & the 3/4 sliding breaker bar & 3ft piece of thick wall pipe. Carefully installing this pinion flange in this way will result in no damage to the flange.
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Buzzards gotta eat... same as worms. |
#15
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I guess if you have this gear swap complete and working properly then you're all set, but if this is still in progress, I'd strongly recommend you thoroughly inspect all these parts and make sure you know what you're working with. All part numbers as well as dimensions and spline counts are readily available on the Internet. Start with the part number for your differential housing and take it from there so you know what you've got.
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Hoping to finish a project while I'm still able to push the clutch in.... 1963 Tempest Convertible (195-1bbl, 3-speed transaxle. 428 RAIV, 5-speed, IRS planned) Pictures |
#16
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See if you can obtain an earlier Pontiac 10 bolt Keep it pure....
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