whats the difference in lengths between a C6 auto and a mazda 5 speed? im thinking of this swap and i want to see if my driveshaft length will need to be changed. thanks for the help!

 

I don't have any idea. But, I bet Murphy's Law will play a part.
I haven't seen a c6 since 1998, on a bench, at a tech school, as a training device.

 

I know a 4x4 mazda is the same length as a 2x4 c-6 from the engine to front of the adapter on the back of the mazda and the engine to the front of the tailshaft on the c-6, so I assume they are the same length if the tailshafts are.