The engine would be an Allis Chalmers G230. I would try your local Komatsu dealer. When Komatsu bought out Kalmar AC they also bought access to Allis Chalmers service parts. The service parts were shipped out of Kansas City.
Upon suspension of the Kalmar AC & later Tusk brands and the movement of Komatsu out of GA - it may be difficult to get an answer to your needs. But you will need a serial number. However, Komatsu has a factory store in the Chicago (Bedford Park ?) area and a fellow by the name of Scott Eller would be a good contact - used to work for Allis-Chalmers & Komatsu - once upon at time.
As I recall the serial number is stamped into the frame on one of the two frame rails, which would be 2" x 6" on that unit.
FYI I know Scott E. from my Allis- Chalmers days.

Dear autry_h this forklift of yours deserves a spot in our forklift museum. Can you post a few photos of the machine in the Yale Oldest Truck gallery on this website? The competition has expired but the form still works. There are plans to take away the upload form some time this or next week...
You can find the form by clicking the 'PHOTO GALLERIES' in the left margin of this page.
We would love to feature your machine!
Kind wishes, Forkliftaction.com

Yes, it is OHV. Thanks for the help.

If that's a overhead valve motor then it's a Allis Chalmers G230