I have looked through the archives and several threads on converting from a 4sp (example: NP435) to a truck C6 (we will use a LWB as there seem to be a lot more of these than the SWB C6). Below is a list of parts that I have seen for a complete swap, some may not be needed as the factory parts may work, please let me know what can be used from the original vehicle.
Assumption: Both trucks are equipped with a 360/390 FE
Parts List:
Auto Steering Column
column to transmission shift linkage (will an extension tab be needed if both are an FE truck?)
transmission to carb kickdown linkage
C6 transmission
neutral safety switch (will the original work?)
transmission cross member (will the original work?)
speedometer cable (will the original work?)
driveshaft (I have seen that the original will not work because of length? and a difference in the yoke? what is the best solution to resolve these differences? will a difference year truck unit or car unit work?)
I think your list looks complete. I think the neutral safety will work. Speedo cable will likely be too short, but the fitting should be the same. Regarding the tranny cross member. I have looked at these pretty closely, but not off the vehicle side by side. From what I can tell, the C6 and 4spd trannies share the same cross member. When I do this switch, I am going to use the original one regardless. May require some fabbing, but from what I can tell, it won't.
Since you need to have d-shaft work done anyway, I would just let the shop handle everything there. Unless you find a factory d-shaft in a bone yard.
I got my cab off my truck the other night and the only things left on the rolling chassis is the engine, tranny, and transfer case. I am SOOO tempted to put a C6 behind it since it would be easier to do right now...or after I get the chassis redone. I currently have a new process 435 4 speed. About how muh would it cost to install a c6 instead of the 4 speed? I do have a c6 2wd tranny that is actually good. Anyone wanna swap? I would love for my wife to be able to drive the truck. She would look BAD ASS showing up to school to teach in this badboy
You could teach the teacher how to drive the stick. JUust remind her that little kids can do it.
Don't forget if changing columns that power steering columns have a shorter shaft so get the same as you have.
Also I keep trying to huck off this C6 shaft front half with a slip yoke for a car style tranny. If anyone needs it for a swap. It was in a 71 or 72 that had a 460 C/6.
Great ideas have always encounter violent opposition from mediocre minds.
I would love for my wife to be able to drive the truck. She would look BAD ASS showing up to school to teach in this badboy 
