No, they didn't always have in/out boxes. I suspect in 1935 there were few if any available production boxes and that it wasn't until a few years went by that the myriad of the combination of in/out and over and under and sun gear style gear change boxes started to appear. Likewise, I'm lead to believe that the first quick change rear axle (Voelker?) didn't appear until perhaps 1939. So there was a transition from the in/out change box to the in/out only box used with a quick change rear, to today's quick change with the in/out shifter function now incorporated in the unit housing. The transmission, was also used (and is in Vintage cars) sometimes with a clutch, and sometimes not. Not having a clutch and flywheel let the engine rev up quicker, eliminated possibility of an exploded clutch or flywheel, but created the need for a coupler from the back of the crankshaft to the transmission input shaft (clutch shaft). Perhaps someone on here has an Ambler, or similar in/out box with change gear section that can measure the distance from the mounting flange to the center of the torque ball housing for you...I have only a Halibrand in/out, no change gear section, that measures 6 inches.