JR:

I can't see why a plan would be needed. Attached picture shows my 40+ year old E_Z Just stand with a Saito FA-30, and a FA-150 mounted on it. The left pedestal slides sideways to accommodate anything down to an 0.049 engine, anything with beam mounts. Granted, I wont run a 140 at full throttle on it, but it's fine for a 4000 rpm break in run. The bottom left picture shows the metal pegs that fit into the lug holes to secure the engine.

Bottom right shows a later commercial stand, construction should be obvious. I've had 38ccm engines at full power on it.

Bill.