Your 4 speed probably has the old square bell to trans pattern.

Later Fords switched to a more trapazoidal looking "butterfly" pattern.

Serving suggestion: Get a 300 with a trans attached, maybe even a 5 speed.

Depending on your use and axle, the Mazda box would work for light duty, road-oriented, or the ZF for heavier hauling. Both require a juice clutch--does your truck have that already?