Just dropping a few pictures of the latest project, Haban model 414E 48" sickle bar made for WH.
Maybe somebody knows better, the closest I could find was this fits about 1968-1973 model WH with 8-12 HP. After removing the center Attach-A-Matic, the gearbox fit perfectly and the front hangers fit the front axle with one small change. I had to make the rear hanger. The lift mechanism was the problem, it had a chain and pulley mounted on a off center lever. I wanted to use hydraulic lift, so my fourth design finally worked. That came with a lot problems, I had to move the drive axle over about 1 1/2" to make room for the lift lever, move the gearbox about 1", and reinforce the frame work because of where I was lifting it. The original gearbox gears were shot, so I found a Jacobsen 48" snowthrower gearbox, NOS made by Haban with the same casting numbers. The output shaft was keyed instead of splined, so I had to make a new front half driveshaft to fit. I cleaned and left all the original parts as I bought them and painted everything I made.
The lever is connected with short chain and slides in the U-shaped block. I've been looking for some type of manual for this exact model with no luck. Not really necessary because I've found that very few parts are available.
Craig