gas to diesel conversion

[mmusmanno]

basically, I dig the truck, so, I want to do it right. i'm not married to a 6.2 or a 6.5, just thought it would be simplest. but, i'm all for a cummins. what would be the best engine/setup for performance? horsepower AND torque? my local mechanic will do the job but he wants me to get a donor vehicle. so, if you guys agree, what vehicle should I get, if not, then what do you think is the best way to get this new powerplant and get it in? thanks.