Been working on a Top Kick tow rig for the last year(+) and finally getting close to done...except...this truck has the 190hp 3116 Cat with the Allison AT540 tranny (good for 540 ft-#'s torque). Looking to turn up the Cat to 300(+) HP but the tranny probably won't hold. Anyone know if there's any better upgrade other than the MT643 (640 ft-#'s) ?? I'd like to get something good for 800-900 ft-#'s since I'll be towing around a 20,000# boat. I know many people have turned up the output on these rigs and any help from someone who's been there-done that would be appreciated.

Theres a guy that I believe is called Suncoast Tranny's or something... He does serious upgrades.
You can probably find the info at www.dieselplace.com