I was wondering what a 4L60E can hold when built up. Like 450-500-550-600-650??

 

someone mentioned it in another one of your threads. gm rates them at 360hp

 

Performabuilt has 3 that I know of.
I think their level 1 is good for 500, level 2 for 700 and level 3 [don't know about the hp rating on that one]
I don't know if that rating is for a full weight f-body or not, but a lot of people here are happy with them.

 

I personally like RPM out in Indiana. Depending on what your goal is for your car they offer many levels to their trans and what they each can handle. Good luck