Just to make sure i have a junk 86 TA, with disk brakes and posi 342. Im swaping it into my 92 RS convt. The rear ends are the same right. Just want to make sure.

Are you sure it's a 3.42? Because I thought the T/As got the 9-bolt that year and 3.42 is a 10-bolt ratio. Maybe it's a 3.45 rear???

Either way it'll bolt right in. If the RS has a drum rear you'll want to swap the prop valve also.

The rears will swap right accross.

If your going from drum to disc make sure to swap out the parkling brake cables as they are different. For the prop valve, I modified mine since I didn't have the correct disc unit. Look back for a post on removing the proportioning piston and spring from the valve. I did that to mine and haven't had an issue. I know several other here have done the same. There is even a post complete with pics if you search on the whole issue.

NOTE: I do not endorse anyone modifying their braking system unless they understand that the results may cause serious issues with safety. I am only relating my experience. It is also noteworthy to add that I run a front compound pad on my rear brakes. I do not know if rear compounds are harder of softer so your results may be very different than mine.