Hello Andy,
There are some differences depending on the model year. They are not insurmountable. Even the clutch assembly changed near the end of production. Most differences are merely bolt up items. The basic gear boxes themselves are identical on the outside. All items like the bell housing, front cover, rear cover, and top cover will unbolt and interchange. Even sedan gear boxes will interchange simply by unbolting items off your original gear box. Internal gearing of the sedans is different at least first gear as I recal, but it will work in a pinch or you can switch the gears also to make it as original.