Originally Posted by OkieTunnel

Its what you have on the front of your blowers. My belts are 16 rib belts, they can slip if the motor backfires. (the ribs run in the same direction as the belt). Your blower belts have "teeth" that run perpendicular to the belt...They are known as cogbelts and they cant slip if the blower backfires. You should have some sort of relief plate or valve on your blower that let it "pop off" pressure if the motor backfires otherwise you might lift the blower right off the block. I think you might have had belts more like mine on your last blowers if they were 250's?