My '87 Camaro Sport has the V6 engine, and is equipped with the automatic overdrive transmission.

1) I want to upgrade to a PowerTrax locker in the rear. I was told that a Monte Carlo locker (made by PowerTrax) would fit the Camaro V6 as long my car had the 26-spline axle. The problem here that exists for me and all V6 owners is finding the correct interchangeable or compatible PowerTrax locker that isn't listed in the Camro V6 categories inside catalogs or websites.

2) Secondly, what size is my ring & pinion gears for the rear differential? I read that the V6's R&P are more favorable than the V8's R&P, but I am not positive on exactly how increasing or decreasing the ratio #'s effects or enhances the performance, torque, or speed. By today's performance standards, what is an ideal performance street ratio?
I am going to up the performance level of the engine and perhaps do a torque converter swap, that is the reason for this concern.