After running a worked over 24p Tempest for the last year the 21p Thunderbolt is like adding a 100 shot of nitrous. Out of the hole in a boatlength and screams to the 6000 redline/alarm at 56MPH. Mileage is better too. We went over 70 miles on about 12 gallons of fuel cruising at 3500 to 4000 RPM -- 32 to 38 MPH. I have yet to hook up the Smartcraft gauges.. Time to get to cracking on some projects..
