Jim,
where did you get this info from? the prevous owner? or off the engine block itself?
Engine is a 4G52 #JW2735

if you look in the side of the block this info is stamped into it. Didn't see anyone mention this but there is a place about half way down the drivers side of the engine block that is a flat machined off square that has the engine model number stamped into it, maybe even the serial number too.
I'm assuming this is where you got those numbers from?

After looking up this truck by serial number you gave it could have either of these engines in it, one you mentioned
4G33, 4G52 or 4G54.
I would look on that place on the block and verify this.
As for putting an automotive engine in?
i would advise against this, not designed for forklift applications so it might be more trouble than it's worth.