I dyno tested one on 9secondPhils 418 C.I. W2 motor versus a Speed Demon 850 with downleg boosters on back to back test, the Mighty Demon made less power and torque than the Speed Demon did. I also tested a Holley 1050 Dominator using a adapter and that made the most power and torque of any of the three carbs. See if that shop has a Speed demon 850 with downleg boosters and get it or a King Demon or a Holley 1000 HP with downleg boosters or a Holley 950HP or a Holley 1050 dominator, if you can get one at a good price