My Garmin GPS is recording 70.6 mph in heat trim. Does this speed sound about right or is there more to be had? Setup specs: Eagle SGX MAC 67, bar stock AB67 set at 10 3/4", negative 1 1/4 degree strut, H-38 w/5.29 cup, front sponson attack angles L-2.30 R-2.40, 50% red max probably 4 gallons...