We have a '93 Topkick with a 366 gas, Allison 5spd auto, it won't go by a gas station!As you can imagine,I would like to repower the truck. I have a good running 210hp 3208 Cat that I think shares the same bellhousing pattern. OR I'd like to go with a DuraMax. Do I need to swap out the tranny? I know the rear end gearing will have to be changed, and I need a computer and exhaust and poss drive shaft mods. But,has anyone done this. I really like the truck and it suits our needs to a T so I'd like to keep it. Thanks for your feedback. Reply to my email address if you could thanks Rodger