Time for a V8. Right now I am still in the planning and research phase. I'm looking at the Gen 3 & 4 Chevy small blocks(most likely a truck 5.3). The GTO's 6.0 has a front sump pan from the factory that will interchange. After a lot of measuring the only fitment issue I foresee is steering box interference with the headers. For the transmission I'll probably use the TH350 from my first swap. C5 & C6 Corvette motor mounts look like they may be modified to fit. A big plus is the Chevy fuel system is near identical to the crossfire, 58psi base with the regulator in the tank. I still have a lot of reading to do and probably won't get any parts till after I close on the sale of my house mid November.
It's funny a month ago I was layed off from work and looking at selling the car. This week I got a decent offer on my house and a call from Navistar asking me to come back to work.