Speed shifting with no clutch

I've got a 94 5 speed and I've heard from different people that when they raced they didnt clutch at all. They would just let off the gas a little and shift as if they were clutching like normal. Has anyone ever tried this before and if so, how harmful is it to the trans?

POWER Shifting

That's what we used to call POWER SHIFTING back in the day. Course, the trannys were more rugged back then too. The way it was done, was to grind off every other tooth on the syncro (blocker) ring. Since you're shifting so fast, the blocker needs extra time to engage. Taking off every other tooth, gives the blocker twice as much time to engage. The M5R2 1-4 blockers have 51 teeth so you'd end up taking 2 teeth right next to each other off.

Last I heard of this being done, was with the Ford Top Loaders, back in the late 60's early 70's. Ford even recommended it in some of their Hi-Po books.

68COUGAR