Driveshaft Length

[hrtbkr]

Hi
I'll be replacing the 7 1/4 rear with an 8 3/4 in my '70 318 automatic (904) Barracuda soon.
I have a few extra drive shafts on hand and was looking for an overall length to fit my soon to be combination.
Does anyone know what length driveshaft I'll need?
Thanks

[Brads70]

This post should help.
https://forum.e-bodies.org/engine-transmission-and-rear-end/4/driveshaft-length/9638/msg133454#msg133454

[hrtbkr]

Can't imagine why there are slightly different lengths for the same combinations, though.
Pretty sure I'll be able to use one from my stash.
Thanks for all the information.