01wss6

iTrader: (4)

Would a shift kit and a 3600 stall be good or bad for a 4l60e transmission with 140xxx miles?

RevGTO

iTrader: (12)

If you are going to pull the trans to do the converter, and even more if you are going to get into it to do the shift kit, with that kind of mileage, you might as well go through it. Read the other thread on the Transgo shift kit for more discussion of this.

01wss6

iTrader: (4)

so i should go ahead and upgrade all the internals while the the trannys off

RevGTO

iTrader: (12)

With that mileage, if you can afford it, yes.

01wss6

iTrader: (4)

do you think it would be cheaper to have the tranny rebuilt and upgraded or buy one thats already built

RevGTO

iTrader: (12)

A built transmission from one of our sponsors would be your best bet for performance and reliability. You can probably find a local builder who will do it for less cost, but you MUST use someone who specializes in hi-performance builds of the 4L60e. Other than those two options, you'd be better off just leaving it alone and having some electronic tuning done on it.