A friend (yes Greg, I have those) just pulled apart his 4-speed that wasn't shifting too well and found these brass synchro rings installed in the 2nd and 3rd position. They have the dog teeth machined off; 1st and 4th position are stock.

I've never seen anything like this, I assume it is some form of "slick shift" mod; anybody here seen this? He bought the trans and installed it without removing the side cover for inspection.