There are some variables between cars. I would install the pinion yoke you will be running, and the tranny. Measure from the trans tail shaft seal surface to the mid point of the bearing cap on the pinion yoke ( this is the flat suface that the strap bolts to ). Give this length to whoever you choose to build your drive shaft. I use DynoTech. Brian
I forgot one thing. The vehicles wieght must be on all four tires as if it were sitting on the ground, when you take your measurements. Do not measure with the suspension hanging. HTH