Ok... I have nearly had it with these damn carberators. Brand new crate motor (less than 3k miles), I got the 350 HO Deluxe - carb to pan complete. It was running great the day before yesterday, today its running so bad its nearly undrivable. I can accelerate from a dead stop just fine, doesnt seem to be a problem. However, while "at speed" or 1/3 throttle I try and accelerate (2/3 throttle) and the damn truck all but dies. RPM goes up a little then down significantly and the truck seems to be starving out then it will backfire through the carb and catch back up. WTF? Help?