Its a model Thd.
I even have one thats been rebuilt but is a parts unit. This one was(is) on a three phase generator that ran a machine shop on a farm in upstate NJ. I purchased it from someone I know who was the origonal owners son.
I would be surprised if it has 50hrs on the rebuild but it sat partially in the weather when the roof caved in.
Rusty sheet metal and wiring damage are the extent of its problems. It has .010 pistons and new bearings.
Internals are nice and clean, no rust or damage from sitting.
Is yours a V4? If so much of the parts are interchangable between this(THD) and one of the V4 models.
Same heads, pistons, rods and so forth.
I currently have the head off if you want some pics.