any difference in length, between s13/14 sr20 transmissions? Or maybe s13 w/ ka box?

I got Dan's aluminum drive shaft from Patrick's car, and when i went to install it into my car its too long.

we both have s13 sr20s
stock differential (open vs his 180sx vlsd)
s13 coupe chassis

only difference I can think is motor mounts, I have solids he has unknown stockish ones. But when I look at my engine, it looks more forward than most not more rearward.

I am trying to get this done today so I can make the event!