Add your abody driveshaft length for quick reference

A 108 wb with 904 & 7 1/4 to 8 1/4 swap the difference between 7.25 and 8.25 housings is 1.25 so what ever your original drive shaft measures minus 1.25.

Here is some other tech I've found from here:

108"wb with 440/727/8 3/4=46.5
904/8 3/4=49.25
add 2.25 for 7 1/4
subtract 4" for 727
8 1/4 D shaft is 1.25 shorter than a 7 1/4 D shaft
727/8 1/4 48.9 w/ 108 wb

111" wb w/ 904/8 3/4=51.99

Make sure your yoke isn't tight in the trans & leave about an inch out for play.

feel free to add your set ups so others have a quick reference