i am running a 750 speed demon on my 408. I love it know but when i first got it out of the box all hell broke lose. Dumping gas in the motor.

I took of one of the bowls as there where metal chips behind the power valve one screw for the float half-way back out.

I sent it back to demon they sent me repaired it for me. " i did pick-up the carb about 3 months before i put it on the motor."

motor runs great i played with the vac. sec. springs runs just as hard as a DP carb IMO.

The choke setting i found to be very sensative.

If i would do it again i would of went with the mighty demon but you do lose the choke which would not too be fun in cold weather.