hp limit
#2
As long as you can keep the tranny cool, it will last a lot longer. Put a nice aftermarket tranny cooler on it. No one can really say for sure from one tranny to the next on how long it will last, I've heard of 4L60E's going out under stock power in low mileage cars and I've heard others that run their cars at the track every week with some pretty modded motors and they last for years. A lot of it depends on how the tranny has been treated, how often the fluids have been changed, how hot it's got in the past, etc. You also have the stock converter so it won't get as hot as it would with a larger stall. I'm running 400rwhp and I'm on my stock tranny with a nice cooler so it can be done, just be careful.