LOL...the 21/43 was retarded unless ya rode the HM 151 700 in MN. I cut the head (before I met this Kelsey guy), 20 top gear, heavy rear springs, 100 lb center shock spring, tossed the 293X ramps in the garbage put in 287 or 299 or 300's all worked alot better than stock...and that 2000 700 was a runner...I did 156 and 159 tracks in those sleds...19/43 was good...remember these were only 15" wide 2" tracks...BJ