904 to 727 upgrade.

Shift lever on the trans may need to be switched out/modified depending what you have (there were different lengths and linkage attachment methods dependent on year and application), but you should be able to make the rest of the linkages work. The slip yoke and driveshaft are different as you mentioned; d.s. length should be the same as for a 727/8.75 combo, but not sure which size u-joint your 8.25 takes. Trans mount is the same.