A Hurst shifter for a passenger car will work. I think the original Hurst company quit making shifters for many years. I think Mr. Gasket bought the name and started making shifters again. A passenger car shifter from the early 50's will fit, but you will have to modify the stick something like this to clear the seat.

http://www.hurst-shifters.com/products/5388620-replacement-bench-seat-stick/