12 bolt to g-body questions

[79olds1985]

can some one please help me and let me know
A. what length i need to narrow my 12 bolt to fit my g-body cutlass and.
B. where and how far from the axle flange should i mount the spring perches to use stock location for springs and,
C. can i take my spring perches from my 7.5 and mount them on my 12 bolt. thanks alot guys.


oh the 12 bolt is from a 70 cutlass if that helps

 

[LS6 Tommy]

Careful, that could be a GM "O" type rear. Can you post a pic for ID puposes?

Tommy

 

[79olds1985]

what do you mean o type? its from a canadian built 70 olds cutlass and those were chevy 12 bolts in those cars

 

[LS6 Tommy]

Many 70 Cutty's got the "O" axle. It has 12 bolts on the outside, but the ring & pinion gear has only 10 bolts & measures 8.2"...

Tommy

 

[79olds1985]

ok but im changing ring and pinion can i put a 12 bolt spool in there with 12 bolt gears? will that work or is the housing made for 8.2 diff and a 12 bolt will not work if that makes sense

 

[LS6 Tommy]

The 12 bolt R&P doesn't go into the "O" axle. IIRC, some minor parts interchange, but nothing that would make the rear better or stronger. Can you post any pictures? I'd hate to get you worried over nothing. Let's figure out what axle you have before we panic...

Tommy

 

[79olds1985]

the diff has 12 bolts on the posi so i think im good what othere characteristics should i look for?

 

[LS6 Tommy]

If you have 12 ring gear bolts, it's the "good" 12 bolt, not an "O" axle...

Tommy

 

[79olds1985]

Awesome and sweet. Thanks for the info