The difference is easy, The model number (found stamped on the block or tag on the valve cover) will be formated like XXXX-XXXX if the 5th digit is 1-4 it is left handed, and not suitable for a vehicle.
If the 5th digit is 5-8 it is right handed.
For example the last engine I picked up is 5043-8301 and translates to:
"5" 53 series
"04" four cylinder
"3" fan to flywheel industrial
-
"8" right hand rotation with blower, exhaust, and oil cooler on right
"3" turbocharged
"01" specific model number and odd number indicates starter and blower on opposite sides.
On an inline 53 series the model number as well as the serial number is on the right side of the block close to the top and close to the rear; viewed as sitting in the drivers seat.
Grigg
