It's a little hard to say whether yours could be shortened or not, with out seeing it. Hurst made a short shifter for 4 speeds I don't remember seeing one for a 3 spd. There are several factors affecting the the throw. The lenght of the shift lever from knob to pivot point, and the lenght of the lower shift lever from pivot point to rod linkage. The shorter these are the shorter the throw. Another consideration might be the angle of the shift lever. If it isn't already back to the seat you might want to see if it be made to get there. You might take a look at the shifters on that auction sight and compare to yours.
Larry

I don't own a vehicle that isn't old enough to drink.