Ive got a 82 Chevy 1/2 ton, and it will not go past 1,000 RPM's in Overdrive. I put an Edelbrock carb on in May, and it ran fine in overdrive for about a week. Then the RPM's get low, it starts jerking really bad when going up a little hill, you can floor it and the sond of air going into the carb gets loud, and it makes this weird sound I cant describe (the truck has an exhuast leak, and the exhaust leak sound weird). If you shift it into 3, it runs fine and even if you floor it, wont go past 2,200 RPM. Then, one day in Sptember, it ran fine. The next day it done that same stuff...messing up.