Im not sure if this is the right place to post this thread but I'll give it a try here. My brother just bought a 95 F-800 with a 6bt Cummins with an Allison Trans. How much can this engine be tweaked, can you go as far as you would in a pickup? Also am looking for an exhaust brake kit, any ideas?

 

Hopefully the Allison is an MT643 or 653, and not the AT545. For more power, it kind of depends on the weight he plans on hauling around. If it's loaded to 30k everyday of its life, then all I would feel safe with is sliding the fuel plate full forward. If it's just a big pickup, then do whatever you would with a 12 valve in a Dodge. The universal exh brakes should work just fine with it. If you call around to MD truck bone yards, ask for a retarder for the Allison(which ever one he has). They give WAY better braking than the exh brake. It's like a torque converter in reverse, bolted to the back of the trans. We got a few aftermarket ones at work, made by Voith, and they are such a life saver!