Building "snot" out of '89 D-300

[dustydog]

I have an '89 D-300, 330,000 miles, previously poorly maintained, auto,12' bed dually. I want to keep the benefits of the mechanical injection yet wish to be able to at least keep up and even "spank" the new truck owners. I do know that due to the limitations of the mechanical injection the truck has to be "built" for a single purpose. I.E. Drag,Tow, Economy. I use the vehicle for work as a Stone Mason so I haul frequent loads in the 3 ton area. I'd like to tow, yet the brakes aren't up to it. I'd like a rig built to tow/haul and have a theoretical 600/1200 hp/tq rating and a stick. Empty, the truck is a svelt 5600 pounds with passenger, dog, few tools, crap behind the seat and a tank of #2, so a bit of power and she should come alive. I only have so far kept the oil clean, upgraded the intake filter and cut the exhaust off at the muffler instead of changing the system from the muffler back. I hope to have another engine in the next month or so from a '92 I'm buying for $2,000. I planned on using the 138,000 mile '92 in my truck while I freshen up my smoky '89 and getting an intercooler out of the deal ('92 is 4wd auto) Would I be better off building the '92 or my '89? Are these engines sleeved or do I have to bore/hone cylinders? I'd prefer (for asthetics) to keep the original block. Can a 24 valve head work (bolt up) and still have mechanical injectors? Would a pump from a larger cummins (semi) be fit? What kind of manual tranny could I use that would shift realatively quickly and hold up to the weight and power? I have no problem whatsoever with cutting up the floor for a dog house to keep a huge tranny. I'd prefer a manual tranny but an older mechanical Allison auto would be ok if it would get all future power to the hopefully smoking duals. I'll have about $5,000 to start and always get a couple decent "cash" jobs here and there. I just want to start learning more and come up with an intelligent, comprehensive, effective and cost effective plan yet maintain some longevity because I plan on trying to get a million miles from this rig (I'm only 43). Lets get started, I have a more than decent mechanical ability and a friend with a heavy lift and alot of time. Oh, for now anyway it's a 2wd but....?