It is not a straight swap. The C4 version works with an external hydraulic slave cylinder with a lever mechanism to achieve a variable percentage of lock. Without that variable lock mechanism, you won't have much if any lock. Also it uses different axle flanges. I'd say to keep looking.
Fwiw, the 4wd version of the gearbox is a G64, not a G50. Only a few parts are shared, most everything is different between the two.
