wyoduster
live free or die
Need to know what rear this is I'm thinking 8 3/4 .. there are 10 bolts around the thing. Reason is I'm looking for better driving gears 3:23 or there abouts and need to know size first for sure.. This is in my 67 Fish..
Need to know what rear
- Thread starter wyoduster
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horsehead
Well-Known Member
Its an 8 3/4 with the 489 case.
HotLines
Realist - Free Thinker
now since we know its a 489 case in a 8.75 housing now leave the jack under it and put jack stands under the body, then crawl under the vehicle and mark a horizontal line about two inches long on the driveshaft with a piece of chalk.
Mark the bottom of one of the rear tires at the 6 o'clock position with a piece of chalk.
Use the chalk mark on the rear tire as a reference and begin rotating the tire by hand from a position that allows you to see the driveshaft.
Turn the rear tire one complete revolution while simultaneously counting the number of revolutions of the driveshaft indicated by the horizontal chalk mark. Be as accurate as possible.
Determine your gear ratio, which is the number of driveshaft revolutions that were made in relation to one tire revolution. For instance, if your driveshaft rotated three and one half times in relation to one tire revolution, your gear ratio is 3.50.
Use the hydraulic jack to raise the vehicle high enough to remove the jack stands from under the axle housing.
Mark the bottom of one of the rear tires at the 6 o'clock position with a piece of chalk.
Use the chalk mark on the rear tire as a reference and begin rotating the tire by hand from a position that allows you to see the driveshaft.
Turn the rear tire one complete revolution while simultaneously counting the number of revolutions of the driveshaft indicated by the horizontal chalk mark. Be as accurate as possible.
Determine your gear ratio, which is the number of driveshaft revolutions that were made in relation to one tire revolution. For instance, if your driveshaft rotated three and one half times in relation to one tire revolution, your gear ratio is 3.50.
Use the hydraulic jack to raise the vehicle high enough to remove the jack stands from under the axle housing.
caferacerx
BAND MEMBER
if it has a sure grip lift both wheels and put on jackstands
if it has an open rear it will be difficult to rotate both wheels an equal amount, and if both wheels are not rotated exactly one full turn the resulting movement of the spyder gears will give you an inaccurate result,
so with an open rear lift one wheel and put on jackstand, leave the other wheel on the ground, rotate one full turn, count revolutions of the driveshaft and multiply by 2,
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