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Old 10-16-2012, 02:04 PM   #5
luvbowties
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Location: southeasternfoothillsofusa
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Thumbs up Re: Rear end gear forum?

Quote:
Originally Posted by Touchdown67 View Post
I have a 65 c10 with a 12 bolt rear end, what is the best way to determine what gear ratio it has? The rear end is making a little noise. It has a SB400 with a 700r4 transmission with 275/75/15 radial tires. Would it be good to consider 373 gears?
Here's a good explanation to help determine ratio. Add to it: "just over 3 revs=3.08; 3 1/4 revs =3.23; 3 1/2 revs=3.55; 3 3/4 revs=3.73; a tad over 4 revs=4.11; 4 1/2 revs=4.56; ...etc."

>> http://www.ehow.com/how_12156231_cal...ear-wheel.html <<

I presently have a 3.73:1 gear, 5.7 Vortec about stock w/headers & 4 bbl, 700R4, and 275-70-15(?..or 265-70-15?) in my '66. I'd say it performs about flawlessly. In overdrive, the 70% reduction of the 700R4 gives (3.73X.70) a 2.61 final drive for hwy cruising. Plus, that extra-low 1st gear provides about all the launch you can get away with around town with so much traffic and so many lawmen.

HTH. sam
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