Rearend gear question

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Oct 8, 2017 | 07:34 PM

#21

LenWoodruff

Burning Brakes

Joined: Jul 2017

Posts: 1,114

Likes: 149

From: Frisco TX

Quote:

Originally Posted by jb78L-82

Yes all L-82 autos had 3.55 gears...documentation above^^^^

If you are getting 3,000 RPM @ 60 mph with 3.55 gears, then yes your tach is off as well since the 3.70 geared cars were @ 2,860 RPM at 60 mph. You should be no more than 2,600 RPM with 3.55 gears..@ 60 MPH.

I changed from 225 70 series toe 255 60 Series. Would they be the same height so the speedometer is correct?

Oct 8, 2017 | 08:20 PM

#22

jb78L-82

Le Mans Master

Joined: Oct 2007

Posts: 7,455

Likes: 977

From: RI, Now Franklin/Nashville TN

Quote:

Originally Posted by LenWoodruff

I changed from 225 70 series toe 255 60 Series. Would they be the same height so the speedometer is correct?

Those 2 sizes are equivalent overall diameter so that would not be causing the difference....

Oct 10, 2017 | 12:18 AM

#23

63mako

Race Director

Joined: May 2005

Posts: 10,674

Likes: 122

From: Millington Illinois

St. Jude Donor '08-'09

Quote:

Originally Posted by jb78L-82

Here you go for 1978^^^^^

Almost all L-82's with a 4 speed had the close ratio gears and 3.70 gears. The wide ratio 4 speed which I have never been able to document how many were made were very rare and COULD come with a 3.36 rear gear.

All L-82's and the auto had to have only the 3.55 gear....

L-48 4 speeds came only with 3.36 gears

L-48 autos could have a 3.08 or 3.55's

Sorry, my error.