I have a 750 no choke Speed Demon on my mild 406. I have not taken the car back to the track with this car, but on the street I also experience a slight stumble off idle. It seems to do it when the temp. is under 160 in the engine. Is this because of the no choke?(TOM?)I like this carb otherwise. I had a 700 holley for 10 years which now needs to be rebuilt. I switched over to a 750 vacumn Holley (I know, don't bash me too hard I've always had mechanical secondaries till now) and had problems with that carb from day one. In defense of the Holley, I never made a serious effort to tune the secondary opening spring. I bought the Demon after seeing some dyno pulls of a friend with a Holley and Demon. His Demon made about 10 hp diff. I don't know if there were tuning issues here or not, but I saw the results. Time will tell in the spring if this carb is what I'm looking for.I know the Richcreeks (Herdsclan) had problems with theirs by talking to Tom and Amy at Milan at a Royal Pontiac Race Day. I will say that out of the box, the carb makes the engine sound better and the jetting seems to be pretty close (a little rich) by the look of the plugs, but then again the car was idleing a lot and I have'nt had a chance to really blow it out. Just my .02 cents
