Oldsmaniac

Ok my brother bought this rear off Craigs for a 71 Cutlass. Appears to be a Pontiac unit with hourglass rear cover. Older style posi looks identical to the one in my 67, cone type. Is there any truth to what was said in his ad?

Just an update, I searched the web and found where this info came from and I believe most of it is convoluted. The rear has a 4.30 43/10 ring gear. I am thinking this is just the Pontiac cone type posi rear, nothing extra. I have never heard of there being anything special or special HD versions of this rear.



DO NOT CONFUSE THE STANDARD GM 8.2 GEAR WITH THE ROBUST BUICK 8.2 RING AND PINION. BUICK DID THEIR HOMEWORK! NOTABLE FEATURES: BUICK 8.2 USES 10 7/16" RING GEAR BOLTS(SAME AS FORD 9")-- BUICK USES LARGER 27 SPLINE PINION YOKE AS OPPOSED TO CHEVY 8.2's 25 SPLINE-- BUICK 8.2 USES A HUGE 1.875" PINION BEARING THAT DWARFS THE FORD 9" -- BUICK USES OVERSIZE BEARING AND CAP ON THE RING GEAR SIDE OF POSI UNIT FOR STRENGTH-- BUICK 8.2 USES THE MECHANIC'S 3R U-JOINT FOR ADDED RELIABILITY-- BUICK 8.2 USES A MUCH HEAVIER REAR END AXLE HOUSING FOR RIGIDITY-- BUICK 8.2 USES A MUCH LOWER PINION CENTER LINE (HYPOID) IN RELATIONSHIP TO THE RING GEAR PROVIDING MORE TOOTH CONTACT AREA THAN THE FORD 9"-- BUICK 8.2 USES AXLES RETAINED WITHOUT USING THE DREADFUL "C" CLIP- ALL CHEVY 10 AND 12 BOLT USE THIS "C" CLIP SYSTEM AND MANY QUARTER PANELS HAVE BEEN DESTROYED FROM THIS POOR DESIGN FAILING. YES, THIS IS AN 8.2 RING GEAR SET AS ARE THE CHEVY AND PONTIAC, BUT THAT IS WHERE THE SIMILARITIES END. THIS IS AN OVERLOOKED, DEPENDABLE REAR AXLE ASSEMBLY AND NEEDS TO BE REVISITED BY THE "BUICK BOYS"!

monzaz

Well I can tell you all the info is correct -

The 1968-1970 Buick 10 bolt 8.2 rear is totally different than the rest of the GM 8.2 rears.

The line about it having a lower contact than a Ford...??? That I am not so sure about.
Also the facts about strength is always questionable as strength comes from how well the rear is assembled also.

The posi unit is a 4 pinion design just like Pontiac super duty units in the GTO...BUT does have the driver side carrier bearing larger for better oiling and torque rating... again questionable upgrade design as it is not used to this day so really how great was it? Right?

pinion shaft is 1.875 but the tapers down to 27 spline just like a gto 8.2 so the wealest spot is always the smallest diameter of the pinion. The 9" is 1.313 and only tapers to 28 spline... so over all size goes to Buick BUT the Buick rear still has a smaller yoke spline connect so that is where the breakage will occur. Also the metal alloy mix will make a huge difference in strength which again would need to be tested from the factory gears.

all in all the guy really is NOT lying... He is just telling you all the good stuff so he can sell his product. The strength he maybe bending a bit...BUT for the day it was a STRONG rear and had alot of upgrades from other rears that were produced in the Muscle car era.

BOTH covers area identical and interchangeable, Axles are interchangeable with other 8.2 BOP rears, Pinion yoke is BUICK ONLY, Housing cast center is as big if not bigger than the Nodular Pontiac N housing that was also used in the 67 Olds cars before the 12 bolt 'O' type rear was created.

4.30 was extremely rare and highly desirable for the Buick guys, I can tell you that.


Ok?

Jim Mitschke
J D Race

Oldsmaniac

Lots of great info, and thanks for the education! Thanks!