I think a lawn boy could be the donor deck and engine.....otherwise I would have concern on the Oil level.
http://www.machinebuilders.net/plan...ered Sidearm Cutter for Ditches and Banks.pdf
I have the same concern.I was looking into building one of these.I think that the head should point straight ahead or even opposite of the slope.This would keep the oil lower than the piston and prevent oil lock.My grandma did that to an old Wizard push mower and it blew the crankshaft out one side and the rod out the other.