Anyone else use a crash box sometime?

Back in the 70's I had someone grind every other tooth (forget the name of that part) from the innards of a A833/3.09 low gear four speed. I was warned never to shift into second, third, or fourth except using a full power shift. Well, the return road from the end of the 1/4 mile drag strip seemed so long (4.56 rear end) that I began to fudge a little and would shift into second on the way back to the pit area. Before too long, I blew all of the teeth off of third gear (during a power shift into third, it seemed like I had shifted into neutral). I guess it was just as well, I replaced the crash box with a prepared full synchro Mopar, close ratio four speed and my E.T.'s improved some (still power shifting, of course).