12V conversion??
The ole idi's will pull a load but certainly not win any races. I think you can still buy turbo kits for them and such and turn up the fuel, but never gonna win any races. Might be able to find a used turbo kit, or make something. I am pretty sure Banks has stopped producing the sidewinder kit, but Hypermax or ATS might still make their kits.
We had a 92 F350 crew cab dually 2wd with 4:10's that had the Banks sidewinder turbo and trans command and such, used it to tow a 18k 5th wheel camper. Wasn't fast but it would get it rolling and such and pull some hills, but through I think 30k of pulling the truck went through 6 sets of brakes, 4 transmissions and finally a motor (cracked heads and just cheaper to do the entire motor at the time)
12V conversion might be more money but will have FAR more potential for making usable power. I personally love the ole idi's but after sinking TONS of money into them you might have a VERY hot 300hp
