Rear end gear ratios

[Doug Van Kalker]

Is there a 3:55 gear ratio available for the 10 bolt rear end?

[oPh]

Question could be.... which 10 bolt rearend? :puzzled:

'64-72 Pontiac & 64-67 Buick 8.2 10 bolt offered this ratio & Richmond has version as well ($240 Summit)

'68 -70 Buick 8.2 10 bolt, ratio jumped from 3.42 to 3.64, no 3.55's.

8.5 corporate 10 bolt, no 3.55's (3.42 jump to 3.70's & 3.73's)

8.5 type "O" olds 12 bolt cover 10bolt, no 3.55's

8.2 Chebby c-clip ten bolt. Did make 3.55's. Richmond still makes them too.

7.5/7.625 10 bolt ('77 & later) no 3.55's

Roger

[flynbuick]

Doug;

If you are talking a 70 Buick 8.2 which has the asymmetrical
carrier bearings the chief engineer for Richmond based in Liberty SC says their 355 does NOT fit. It is my understanding that there is no aftermarket gear for that rear.

[70 gsconvt]

Right in Summit's catalog is a listing for 8.2 "B" or "P" rearends with a 1.438 pinion stem. They show 3.55, 3.90, and 4.11 gears.

Items numbers are RMG-4900821 (3.55), RMG-4900841 (3.90), RMG-6903581 (4.11).

[flynbuick]

70 gsconvt said:Right in Summit's catalog is a listing for 8.2 "B" or "P" rearends with a 1.438 pinion stem. They show 3.55, 3.90, and 4.11 gears.

Items numbers are RMG-4900821 (3.55), RMG-4900841 (3.90), RMG-6903581 (4.11).

I went through that once too . Summit uses Richmond if a recall correctly. Just call Richmond's home office in Liberty SC and ask to speak with the chief engineer, I cannot recall his name , and he will explain the misconception over what the gears listed in Summit will fit.

[73-462GS]

oph- What rear end do I have in a 1972 GS 350 Skylark single legger? I would like to go around 3.55 with a posi. if possible. Thanks. Mike D.

[flynbuick]

They changed beginning 71 and I believe you would have an 8.5. The ratio is likely a 2.93, 2.73 or 3.23 if the options are like a 70.
If it has not been changed the code stamped on the axle housing drivers side can be used. Otherwise you would have to measure the ratio of the turns of the shaft versus the wheels. There is a lot of parts for the 8.5.

[73-462GS]

Thank you Jim. Mike D.