7 1/4" rearend question

Posted By: mopowers

7 1/4" rearend question - 02/07/13 09:17 PM

What gear ratios did these things come with???

I've got one pulled and on stands. I'd like to know what ratio it has. Is there a way to tell without pulling the cover???

Posted By: RapidRobert

Re: 7 1/4" rearend question - 02/07/13 09:23 PM

Lock one axle so it is secure. rotate the other axle 2 turns. count pinion rotations. ie 3 & 1/2 turns is 3:55, 2&3/4 turns is 2.76 etc. I am assuming it ain't a sure grip as they are rare (I have 2 of em). If it is a sure grip then dont secure the axle & turn an axle (both will move) 1 turn instead of 2 turns & count the pinion rotations same as a non sure grip

Posted By: mopowers

Re: 7 1/4" rearend question - 02/07/13 09:30 PM

Cool thanks. Is there a list of ratios that they made for the 7 1/4? It's not a sure grip btw.

Posted By: RapidRobert

Re: 7 1/4" rearend question - 02/07/13 09:37 PM

A shop manual for a 7&1/4 equipped vehicle MAY have a listing of what was available or google it. I'd say odds are a 3.23 or 2.76

Posted By: VincentVega

Re: 7 1/4" rearend question - 02/07/13 10:20 PM

There's no tag on the cover?

Posted By: 340SHORTY

Re: 7 1/4" rearend question - 02/08/13 04:29 AM

Why bother ??

Posted By: mopowers

Re: 7 1/4" rearend question - 02/08/13 05:43 AM

Quote:

Why bother ??

Just curious

Posted By: Winchester 73

Re: 7 1/4" rearend question - 02/08/13 05:53 AM

hit the throttle from a stop and count the pinion teeth spread out on the asphalt behind you

just joking, the truth is ive always found 7 1/4 rears to be indestructible untill you get about 100 miles from home

Posted By: chargincharles

Re: 7 1/4" rearend question - 02/08/13 08:05 AM

A Whole Looooottta those came from under F, M and J bodies.
Follow the advice of the above.

This is a listing I have:
�2.26:1 - Used in many civilian M-bodies over the years
�2.76:1 - Used in 80s Dakotas
�2.93:1
�3.21:1 - Used in 90s Dakotas
�3.23:1 - Used in many Slant 6 cars from 1963-1969, and 80s Dakotas
�3.55:1 - Used in 80s Dakotas
�3.90:1 - Used in 90s Dakotas
�3.91:1 - Used in 67 Formula S Barracudas with power-lock

Here is the forum/thread it came from:

http://www.dippy.org/forum2/index.php/topic,73.0.html

Enjoy!
CC.

Posted By: B5 Bee

Re: 7 1/4" rearend question - 02/09/13 05:24 PM

60-69 A body, slant six with auto, usually the 170 had 3.23, the 225 had 2.93.