Is there any way to tell what ratio your rear end is by looking at it? I ask because my car has been partially restored in the past, and I'm curious to know... Thanks!

Brian

In Ernies words ~~~ Search is your friend

txbusa
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Necoa #: 4633
Location: Dallas, TX
Joined: Jan 11, 2005
Posts: 823


Posted: Sat Jul 09, 2005 8:46 am Post subject:

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Gear Ratio = (RPMxTire Diameter) / (MPHx336)

Otherwise you have to remove the differential cover and count the teeth on the ring and pinion gears.

Counting Gear Teeth:

Count the teeth on ring and pinion gears.
Divide the tooth count of ring gear by the tooth count of pinion gear.

Estimate Ratio by Rotating Tires:

•Select a level surface to conduct test (Safety First!);
•Mark the edge of the tire with chalk (bottom);
•Mark a spot on the drive shaft so you can observe the number of revolutions while the shaft rotates;
•Put the vehicle in neutral (Revert back to step one if vehicle rolls);
•Push the vehicle straight ahead (by hand!) until the tire rotates exactly one rotation (360°);
•Count drive line turns as the vehicle moves.

Note: Have a friend push while you do the hard part: Watch and count! (be careful not to spill your favorite legal beverage).

This will work if you accurately count the revolutions. I have a few examples below:

3 turns on the drive shaft will be 3.00 to 1
3-1/4 turns on the drive shaft should be 3.25 to 1
3-1/2 turns on the drive shaft indicates 3.50 to 1
3-3/4 turns on the drive shaft should be 3.70 to 1
4 drive shaft turns will equal 4:10 to 1
4-1/2 turns consider 4.56 to 1
5 1/3 indicates 5.38 to 1.

All this info. I got by searching.

John Don't claim all info. is 100% accurate
_________________
72 SS 454/700r4
(A real SS that got a 454 along the way)
"Great Threads" web site

HOPE it HELPS

unfortunatley you cant tell just by looking .. you can tell if its a 7.5..8.5 .. or a 12 bolt just by looking but not the ratio .. you need to remove the rearend cover and count the number of splines in the gear and the pinion .. thats the easiest way you can tell..good luck !!

its been so long since i did that but Larry is absolutely correct .. You will get an estimate but in order to find out for sure remove the rearend cover and count the splines in the gear and pinion .. thanks for reminding me of that Larry !!

Or try this thread
http://elcaminocentral.com/ftopic-24719-0-days0-orderasc-i.html

Dennis, Me too, It's just the LAZY MANS WAY, and a rough GUESTEMATE