10-12 bolt gear ratios

Post Reply
Newbie Poster
Posts: 1
Joined: Sun Jan 19, 2014 11:46 pm

10-12 bolt gear ratios

Post by mtmay »

hello i have a 10-12 bolt rear end in my 73 lemans stock car and would like to change gear ratios something like 3.42 or 3.55 does anyone know where i can get a ring and pinion or what other differential gears i can put in there with adapter bearing or something to make it work? any info appreciated thanks
User avatar
Average Poster
Posts: 906
Joined: Tue Nov 13, 2007 7:56 pm

Re: 10-12 bolt gear ratios

Post by monzaz »

Well really there are no gears for that rear. IN the AFTERMARKET that is. There is no trick to fit other gears in. Obsolete rear. GM did make 3.42 gears you might find in a wagon or deville from the 1980's (same rear)

Best to find a 10 bolt 8.5 and build it up will be better for parts and just as strong.

IF the pinion shaft inner bearing surface measures 1.875 we have one set (3.55 460.00 a set NEW) BUT that is normally a full size rear...(1.875 shaft size) If the pinion shaft is 1.625 we can not help you.

Easier to just get the 8.5 rear from 1973-1977 and you will have a good stout rear after you install good aftermarket parts. You can upgrade the axles to 30 spline with a 30 spline 8.5 posi and a gear set from 3.08 3.23 3.42 3.7 3 3.90 4.10 4.56 4.88 5.13 5.3 8 5.57

Jim- J D Dace
J D Race
Post Reply