I deliver new campers with a 89 crew with a banks turbo, I added the turbo. I pull campers dry weight 5k to 11k all over the us. Started with it na and added the turbo, pulling the Pennsylvania and rocky mountains the worst I've gotten down to was 45 mph at 230 water temp and 1125 egts with propane injection out overdrive. I've run 100,000 in a year with very little trouble.
The guys with the newer trucks have a lot of computer issues and most of the ones with the 6.0Oho are on the 2nd and 3rd engine which is rough when you have a $1000.00 month payment and the cost of a new engine. Upgrade the idi and stay away from the newer computerized nightmares.