X2 what Screamin said. If you can find a shaft that gives you 3/4-7/8" play with the common aftermarket flat extension housing seal you're good otherwise get a longer one & mock it up & give the dimention to the driveshaft shop & I'd R&R the ujoints yourself (holler if you want some tips) unless you really trust them to be conscientious with the ujoint install then have them shorten and balance it. EDIT as said the 904 & 727 yokes are different & iirc the 4sp/727 yokes are the same but check on that if needed