As crackedback said "using factory components". I'm having a driveshaft made for my '67 and the guy making it for me insisted that I took my measurements using the same yokes that I intended to use. He said that the yoke designs varied and it would affect the final length of the shaft he would make. I was instructed to install the yoke into my transmission as far as it would go and then slide it back out 1" before taking my measurements. This is with the car sitting on the ground.
I got a quick question regarding this post, 73 Duster V8, if Im using a 904 tranny and a 8 1/4 rear. Is there a tnypical size driveshaft Im looking for to work with?