4x4 cosworth diff will fit straight in and you can use the same propshaft and driveshafts if yours is a model with disc brakes on the rear.

4x2 cosworth diff will not fit as it is wider where it mounts into the beam (7.5 inches compared to 7).

hope that helps, and nice car. i would consider importing one some day and converting it to 24v cosworth engine.