Full Size axle interchange

Hi Guys, I have a 1973 Buick Centurion Convertible. It's a 350 4bbl with a posi. Yes, the much sought after full size posi. It's got 240k miles. I went to have the pinion bearing replaced and the shop told me that the passenger side axle tube has broken it's welds and turned 2 degrees. He blew air in between the axle tube and pumpkin and bubbles formed in the holes with the welds. The bottom of the welds looked solid, but the welds in the top of the holes looked broken and crumbled.

Question 1: What axles interchange in full size 73's?

Question 2: Is this even possible? How can a little 350 develop enough torque to twist this axle? It can't even spin the tires. The guy isn't looking for more money and I don't think he's scamming me. But he could be honestly mistaken.

Thanks,
John

 

http://www.v8buick.com/showthread.php?t=75045

you've got a full size assembly ... we still don't know what size your ring gear is. i suspect an 8.5". if i'm right it's still valuable, still useable in all the big cars AND it has the advantage that you can get any ratio ring and pinion you want and any GM 8.5" carrier will work in it. although the lighter construction would explain how it got broken....

how many bolts are in the cover of the pumpkin? has he taken the cover off? how many bolts in the ring gear? i believe the 9 3/8s is a 12 bolt cover and ring. could also be an 8 7/8s.

 

I also think you have a 8.5 rear. If I recall my Chassis Manual, 455 B-bodies got the 9 3/8 and 350 B-bodies got the 8.5. Ofcourse that is just what was supposed to happen, I'm sure things didn't always work out on the assembly line.

 

Is That The orginal engine? I thought all "Centurion's" had 455's. Was the Centurion just a trim package?

 

I'll try and find the axle code tonight. According to another wonderful thread on this board all rear axles 71-76 from b body buicks interchannge (excluding wagons).

RR43500067A is 8.5
RR43500067B is 8 7/8
RR43500067C is 9 3/8

The Centurion came as a 350 in '73 only. I haven't seen any production numbers to indicate how many came as 350 and how many as 455. 350's seem to be rare. Why the original owner ordered a 350 and a posi but not a towing package is beyond me. Probably for the same reason he bought a full sized Buick without any options.

I just checked my paperwork and realized I bought this car 17 years ago. Dang has it been that long?

John

 

Was the Centurion just a trim package?

absolutely not. it was a seperate model line from 71 to 73 with it's own VIN code.

maybe more years, we'll have to see what Smartin says. :laugh:

all rear axles 71-76 from b body buicks interchannge (excluding wagons).
B, C, D and E bodies across ALL GM lines (barring the front wheel drive E bodies). you can also use the gear sets and carriers (and, i suspect, the half shafts) from the wagons, you just can't use the drum to drum assembly without severe custom modification work.