Topic: Limited slip rear end

[kitemare]

My '77 has a limited slip rear end from the factory. What's the difference between a this & a positrac rear end? When I start out & punch it I get the rear end to drift like both wheels are definately spinning, but when I really hit it to do a burn out it sure seems like I've only get one wheel spinning. I can tell from the rubber that is built up on the left rear quarter panel where there is not much on the right. For some reason my tires aren't leaving black marks on the street so I can't tell by looking at my tracks.

Does a limited slip rear end loose traction to one wheel when one side really breaks loose, or do I have a problem with my rear end.

km

[Eagle 1]

Maybe this will help.    This is from Randys positraction website.
I agree with what he says.  Both limited slips and positraction rear ends are basically the same, just react differently.

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Positractions & Limited Slips:
Posis and limited slips transmit equal torque to both wheels when driving straight. However, when one wheel spins due to loss of traction, a patch of ice, mud, too much throttle, etc., the unit automatically provides more torque to the wheel that has traction. Recommended for daily driving, works well in ice, rain, mud and snow. However, in situations where absolute lockup is needed, a limited slip is not the best choice due to the fact that limited slips do slip in some situations.

Positraction is a type of limited slip. The name "positraction" was used by General Motors for their limited slip differential and the name has been associated with limited slips for many years.

http://www.ringpinion.com/content/technicalhelp/default.asp?pid=128

[kitemare]

Thanks Eagle 1, that helped. It looks like if you want a rear end for doing burn-outs you need a locker but that might not be the best for everyday street driving?

km

[Eagle 1]

I think GM used Eaton possitrac rearends, at least back in the 60's and early 70's.  You could build the rearends to be more aggressive by using the heavier clutch pack sets, which is what you might want to do to yours.
Both tires on your car should spin.
I have ordered kits from Randys before.