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Old 10-22-2013, 02:54 PM
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Determining Existing Gear

So! On my '74 Camaro, PO put on a shiny new chrome rearend cover. I wonder if they did any upgrades inside. How can I tell? Is it a tooth-count deal? Or what? Any information would be way-cool.

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Old 10-22-2013, 03:49 PM
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Count the teeth on the ring gear and pinion gear. Divide the number on the ring ear by the number on the pinion for the gear ratio. 41/11=3.73, 41/12=3.42....
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Old 10-22-2013, 05:16 PM
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And if your lazy like me and dont wanna pull the cover, just use math, it will get you close.
http://www.summitracing.com/expertad...tio-calculator
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Old 10-22-2013, 07:10 PM
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Jack It Up

Someone suggested I jack the car up, mark the driveshaft and the tire. Rotate the tire one time and count the number of times the driveshaft rotates. Any merit to this. Seems like it could get me close, but maybe not spot-on.
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Old 10-22-2013, 07:46 PM
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Depends on what differential is in it. If it's a good working posi and both rear tires turn together then that will work. If not the leave one wheel on the floor and turn the other one exactly 2 turns. 3 3/4 turns = 3.73, almost 3 1/2 turns = 3.42. just past 3 = 3.08...
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Old 10-22-2013, 07:52 PM
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Right-On! Thanks guys. This forum and the guys here offering advice and feedback is/are the best. It makes this car really fun to play with. I sold my Harley to buy this car. The test was, that whatever I swapped for had to make me smile the way I smiled when I was on the bike. Gotta say, this car turns more heads than the bike ever did. And I smile with my whole heart when I drive it.
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Old 10-22-2013, 09:11 PM
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Quote:
Originally Posted by James Chatfield View Post
Someone suggested I jack the car up, mark the driveshaft and the tire. Rotate the tire one time and count the number of times the driveshaft rotates. Any merit to this. Seems like it could get me close, but maybe not spot-on.
We put together a few ways to figure out the rear gear ratio, see the page here.

Good luck.
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