4v refers to the carb....you have a 8cyl car so unless it was changed you have a normal WC tranny.....you can get a tranny from a 4cyl Mustang to work if you have no other options but the ones from 8cyl cars are better.
when i was buying my '94 the car salesman tried to tell me it was the first year of the 4.6 and '93 was the last year of the 5.0 even though this was at the point and time where i was checking under the hood and he was pointing at the motor!