im posting this for a friend.

he has a 94z28, its gettin old so he is curious as to his options. would it be better to rebuild his current motor and tranny. or get all brand new motor and tranny. whats the cost of a motor rebuild into a stroker or something like an lt4. also a heavy duty 4l60e and a new rear end will be purchased too, how much is that all gonna run total? 7k for tranny, rear end and rebuild?

 

If he is not having problems LEAVE IT ALONE, milage does not hurt modern injectoed motors like it did old carbed or even TBI stuff. If you do want more power out of it do not jump on the LT4 stuff, there are better cheaper alternatives and the LT4 intake is no longer available anyway.
If looking to push some power through then start looking into a tranny build and use someone specifically with a good rep for 4L60E builds in a performance car I like www.pro-built.net . Just because a shop can build a TH400 for a 9 second car does not mean they can build this tranny for even a 14 second car.