Your four speed is probably strong enough, it was used until 1947, so a bellhousing from a '38-'47 would bolt to the 235 and provide the rear mounts and pedal mounts and the floor start. You may want to use an early 50's or late forties 1/2 ton fourspeed to get sychromesh. The 206 is longer, therefore you will need to extend the front mount plate on the frame and use early 216 front mounts. The information for switching from a 216 to a 235 covers most of it.