Encyclopedia of German Tanks says the H-35 had the small engine and short gun , the H-38 had the large engine and short gun , while the H-39 had large engine , long gun . The rear hull and exhaust layout changed with the larger engine , but pictures show the early hull with long gun labelled as H-39 . Might they have labelled the tank by the gun , not the engine / hull variant ? It dosen't help that the tank seemed to have a longer / more distinguished service life in German hands , then its original owners . And the Germans seemed to swap the gun / turret around from hull to hull as needed , as seen in many pictures . Hmm , need to find a good book on French tanks