Ok, Maybe someone sells Detail sets or PE parts to convert?

Around 1990, MP Models used to offer an M4A3 upper hull in styrene to convert a Tamiya late M4A3 wet stowage Sherman to a dry stowage M4A3, but that kit has been gone for a long time (though you might snag one on E-bay).
You could use the Tamiya M4 Early kit and mate the engine deck and tail plates (upper and lower) from Tamiya's M4A3 kit to produce a late dry stowage M4A3. The movie tank had a mid production suspension system with horizontal return roller arms, whereas both Tamiya kits offer the late type with the upswept return roller arms. If this bothers you, you could swap the suspension with that of an Academy M4A2 (Russian or USMC version), as that kit (incorrectly) has a mid production suspension. Or you could buy a Tasca late suspension system.