Just getting curious about finding parts to swap my 66 big cars over to 3.23 rear gears which leads me to a couple of questions:
1) will the gearsets (ring & pinion) from Cutlasses / A bodies swap into big car rear ends?
2) Does anyone know what the stock ring gear bolt count was, and what the stock rear cover bolt count was?
3) Assuming my cars are stock, am I right in thinking they are 28 spline axles?

I realize I need to check all this before pulling the trigger on parts, but would like to know what I'm looking for...

Thanks in advance
cf

 

I am no rear expert but the 65 and 66 Full size Olds mostly used the Pontiac 10 bolt cover rear. Nothing interchanges to the Cutlass rears. In 67 -70 these cars had the 12 bolt cover Oldsmobile rear. Again I dont think anythjing interchanges to the A body differentials.

 

1.) I assume you have the PONTIAC 10 bolt cover with 12 bolt ring in your Olds? As Olds really did not have a rear until 1967 late which had a 12 bolt cover and 12 bolt ring gear.
So assuming you have the FULL SIZE PONTIAC which LOOKS like the GTO A-body rear...IS NOTHING at all like the full size car rear. Period. NOTHING interchanges there.
2.) Stock 3.23 ring gear count is 13 on the pinion and 42 on the ring.
10 bolt cover for the early Olds full size which really was a PONTIAC catalina rear. *(reference picture attached)
3.) Full size cars in the 1965-1970 early Pontiac and Olds were all 31 spline
NON were 28 spline that was A-body cars (GTO Tempest Lemans Cutlass 442 etc) Cutlass 8.2 cover picture for reference. CLOSE but when you put them side by side TOTALLY different in depth and size. reference attached picture

 

Well I can tell you it will not be an easy task. 3.08 3.23 3.42 ratios are hard to find.

I had 2 sets of 4.33 gears about a year ago NOW that was a find indeed...
I have never had a 3.73 3.90 in hand ever.
A few 3.23 two hand fulls of 3.08 and I do have one 3.42 set right now along with a set of 3.08 Just received them 3 days ago...Nice garage find.

Jim
JD

 

So, net thus far is
1) A body stuff doesn't swap. Makes sense since the loads were different
2) I may have a "P" type rear under my cars or a "B", or an "O" since they used all 3 in '66.

Many thanks for your contributions
Cf

 

according to my owner's manual and a sales brochure for 66 the dynamic 88 ,delta 88 and starfire came standard with 3:23 . I've never actually checked my 66 dynamic ratio. if this is true I wouldn't think that ratio would be that hard to find