I made one by cutting off the pushrod about 1" from the pedal end, then turning that end down just enough to thread it for 5/16". I then made a short sleeve, threaded at both ends for 5/16. One end is threaded with loctite to the pushrod and the other has an ARP 5/16" bolt screwed into it (12-point head cut off and smoothed with belt sander. Now I have an adjustable rod. After trial fitting, you can mark the rod (at ARP bolt) and loctite that end, too. Anyway, I got tired of having play and this was all available to me from stuff I had laying around.
BTW, Scott Drake has one for about $50.