I installed a Fett Bro's heavy hitter clutch weights into my 1997 thundercat . Has to be the best money spent on getting the sled to rock!!! It takes a little time tuning but well worth it, putting the power to the track. No use having the power if it's not going to the ground. I was wondering what other sledders thought of the kit. The two other things that was worth the money is Temp-a-flow, just jet and forget it and the UFO's great throttle response and a great combo.