Old53BBO

Hi guys,
I've been searching the web for three days straight and found a hole lot of info on the 9.3 axle but still have a couple questions I haven't seen answers for yet. I know I'm looking for a 57-58 Olds or poncho 9.3 and seen everything that exchanges and what to use from the latter years but some say the Pontiac axel is shorter than the Olds and some say there the same length. Is it the same length housing just different width drums or?? Another question I want to know is some say the leaf spring perch is different between the two and some say there not? I know moving perches is not a big deal but would prefer not to if I have the option!!! Just want to clear up my confusion from my three day reading binge LoL! My guess is if the perches are different between the Olds and Pontiac axels that the 57-58 Olds axel would be the one that would bolt to my 1953 springs??? Thanks very much!!! Already have found ample valuable information on here just by reading over the years!

OLDSter Ralph

I'll get some of this right, there will be others than will chime in to correct things.
1. 57-58 "pumpkins will fit all the way up to and including. 1964. Where this gets sticky is that the number of axle splines changed after 1958. "Anti-Spin" (Positraction) came out in Oldsmobiles in 1958, but doubt there are any around. You can get Anti Spin and new gears from Fabcraft or Jdrace.
2. Olds and Pontiac axles are the same during some years. When Pontiac came out with that "Wide Track" stuff, the axle housings and axle were different width. The Pontiac differentials were wider.
3. I can't say about spring perch width.
4. Dutchman used to make 57-58 axles with the newer (59-64) splines. I assume Moser makes them also.
5. Monzaz on this site is the resident Guru on differentials. You can PM him. You can contact him at Jdrace.com or (330) 990-8155

Old53BBO

I've read where the 57-58 Pontiac 9.3 is narrower than the 57-58 Olds 9.3. I know the drums are narrower on the 57-58 Pontiac, so do they mean the Pontiac housing is longer to make up for the narrow drums or that the Pontiac axel is shorter from wheel mounting surface to wheel mounting surface? Would really like to know if the springs perches are different, I've read about every article on the web that swaps the 9.3 into about every motor vehicle on the planet except early fifties Olds LoL!!! But the tri five Chevy guys say that the 57-58 Pontiac 9.3 bolts right to their springs and the guys that mounted the 57-58 Olds say that they had to move the perches, so that makes me think the perches are different? I'm looking at one 57 Pontiac 9.3 housing and one 57 Olds 9.3 housing right now and the guy with the Pontiac axel said the housing is 54" and the guy with the Olds housing said it's 54". And looking at the pictures the perches look the same except the Olds has holes for the springs to set in and the Pontiac looks like it has short studs for the springs to set on? But that's just looking at pictures and not using a measuring tape. Would really like to buy one of these, just want to get the best info for my picky butt LoL!!

Old53BBO

Thanks everyone!
looks like Jim answered my width question in a 2014 post I found on this site! The Pontiac rear is slightly wider, must have got it confused after reading multiple articles LoL!