I ripped the spider gears out of my third member a while back. Some fragments got into the pinion and the bearings...so it was toast.
On external inspection I thought that I had a 8 3/4 gear with a ratio of 323. It actually had a 8 1/4 ring and pinnion with a 331 gear.
Randy's differential fixed me up with a 83/4 posi with a 373 gear with the same third member casting numbers. It was a simple bolt in.
I haven't done a hard run yet(breaking it in) But I'm happy with the results so far.

I never would have dreamed my 83/4housing would have had a 81/4 guts.Oh well...

Trysix
1965 Coronet 4dr, not so stock slant six with OD a833 trans .....and now a 83/4 373 posi

soupitup@msn.com

I'm happy with the results so far.
:
: I never would have dreamed my 83/4housing would
: have had a 81/4 guts.Oh well...

If you had an early "741" cased 8 3/4" some of them had an actual 8 3/8" ring in them....

fyi

-D.Idiot

res0aus2@verizon.net

A lot of 57-65 full size SL6 cars had that 8 1/4 gear in the same 8 3/4 housing. You did the right thing by changing over to the 8 3/4 gear set.

Does you rear axle have the taper axle with the bolt-on brake drum?
Dd

Doc,
My axles did not have the drum nut. The drum just slips off and the axles are held in by a flange.
Duster,
It is a 741 case.

Trysix

soupitup@msn.com