I have a 1993 (350) 5.9 diesel. I HAD a getrag 360 behind it. It is dead. I would like some suggestion of what to put behind it. I will be using the truck to pull some 10,000-12,000 at times (not always). 5 speed, 6 speed or automatic ? I want to make this 1993 350 the BADDEST thing in Louisiana. Help.