Hello,

I have gotten back into Z's after a 25 year absence. Back then there was nothing like this forum so I am very thankful for this as well as the other forums and I look forward to your input.

I am refreshing an early 260Z. She is up on jackstands now and probably will be for another year or so. I paid $250.00 for the car and have decided to take her down all the way. I do not have much history as the PO died 2 years ago and the car sat. I will be putting a 5 spd in and after going through the posts it seems that a 3.9 R200 would be the best choice for gearing. This will not be a daily driver but my speed days are over. So to my question, if you had the choice, would you go for the 3.7 LSD or go for the 3.9.

Thanks, Skip

My choice would be dependant on which 5 speed you are going to use.

If it's the 280 speed with the shorter overdive, the 3:70 would be fine.

If it's the ZX 5 speed, I'd choose the 3:90 if I had the choice.

Reason? With the ZX trans, you will still be under the overall ratio you would have with the 4 speed and the 3:36, which will mean your highway RPM's will be lower than stock. With the ZX trans and the 3:70, your highway RPM's will be quite a bit lower than the stock set-up, and we all know the L engine doesn't have a lot of torque in the lower RPM's(under 3K), which would mean if you were to try a pass on a 2 lane road, you'd almost have to drop a gear to complete the pass safely or quickly.

If you have both diffs, try one and see how it works, and you can always swap the LSD to the one that suits how you want the car to drive...

Don't forget, the tire size you choose will also affect the ratio as well, so you will have to take that into account in your choice as well as which trans you are going to use.