I have 86000 miles on my car and I want to make my car into a bolt on 12 sec street car. If my trans is still shifting good do you all think that I need to still have it rebuilt when the stall and shift kit are put in? Also what about the engine. If it has been well taken care of and runs well is it safe to put all the bolt ons into the car and not worry about pistons or the rings? The one internal mod to the motor will be a cam shaft.

 

4L60Es can definately use some modifications in performance cars. The 4L60E, in stock form, doesn't take high RPM's very well. A shift kit won't solve this problem either. There are modifications that need to be made to the INSIDE of the transmission.
The 4L60E can be built to work very well in a modified car...Even those dipping deep into the 10 second zone...If it's modified and built CORRECTLY.

Frank

 

86k is nothing, I have 136k on my 94 and am just now installing LTs. Go ahead and mod it.
Tranny needs to be done by someone who knows what they are doing. Don,t let some moron tell you he can do it without getting some opinions on his work, on the same tranny not some turbo 350, Guy I know had a supercharged 355 in a 94 and went through 4 tranny builders before he found someone that could do it right. The 4L60E can be built to handle decent horsepower the trick is finding someone with the talent to do it.