727 No forward or reverse

I am running around 550 hp. Previous owner of the car did the engine and transmission swap. I am hoping that the trans was built to keep up with the motor. There are kevlar bands in it, also not stock ratio servo levers, deep pan, manual valve body etc.
Trans lasted 8 years before this happened.
Will report on findings soon.

Thanks for the tips. Damn they charge 45$ for shipping to europe in the place you recommend and the shims are 16$ ;-)