Hello everyone, been registered for a while, but this is my first post. I have a 95 F350 Crew Cab that the PO swapped in a 6.6 Brazilian with a 545 Allison and a 7041 Spicer. Anyway, I have a few questions. 1st off, has anyone turned these up, and if so, how much? 2nd, would a 643 Allison be a better transmission? I have to redue the driveline and build some new crossmembers, so if the 643 would be better, now is the time. Let me know what you think and thanks, William.