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Just curious what rear this MIGHT have. It is a 1961 352, 2bbl, 3 speed? I am in 3rd around 20 MPH and I keep trying to find another gear. At 65, it sounds like it is working a lot harder than it should. IF it is still stock, is there some external markings to ID it? I haven't driven a 3 spd. in nearly 40 years, is this how they are supposed to run out?
 

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I know what you're talkin about and I think you have to get used to it.

To check your rear end ratio, jack up one wheel. Put a mark on the driveshaft. Then turn the raised wheel until it makes one revolution, watching the mark on the driveshaft. If the mark goes around 3.5 times you have a 3.5 rear end. Not sure if this works on positraction.
 

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Unless it's been removed or the rear's been replaced, shouldn't there be a small tag on the rear end housing that gives the ratio?
 

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I know what you're talkin about and I think you have to get used to it.

To check your rear end ratio, jack up one wheel. Put a mark on the driveshaft. Then turn the raised wheel until it makes one revolution, watching the mark on the driveshaft. If the mark goes around 3.5 times you have a 3.5 rear end. Not sure if this works on positraction.
That method only works if you have a locker or posi rear end with both tires off of the ground and turning equally....For a regular open rear end with only one tire jacked up you have to double the number that the driveshaft turns..For example the driveshaft takes 1.5 turns to turn the tire 1 revolution..You would double the 1.5 so it equals a 3:1 gear.
 

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+1. With one axle stationary in a open diff, the remaining axle rotates the side gear through the pinion (spider) gears, which causes it to reduce the driveshaft turns by half. For trivia's sake, that also means a car spinning one tire when stationary is making it spin twice as fast as a locker would make it spin. That's why someone spinning their tire in snow looks like it's spinning at 60 mph in 1st gear - because it is. ;)

David
 

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That's some good stuff, there!
 
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