Thank all of you for the input, I know the zf would be best however keeping the c6 will be clean and simple. I only haul hay, tools and scrap with the truck and usually being overloaded, I tend to keep the speeds low. I think the c6 will good, I want to keep the truck as original looking as I can so I plan to adapt 67-72 auto steering column and shifter to the c6 setup. Right now I am expecting a small windfall of cash which will fund this project. I will post more as I get closer to the project start. for now I need to work on finding a source for olives to tighten up air intrusions in the fuel system of my current 6.9 setup.
