I have a 400 ci Pontiac with a 4 barrel Carter carb. It has a weak spot when you ease into it at around 1,000 RPMs and i understand that this is from a lack of a secondary vacuum on the carb. Also, i have heard i would have to buy a Holley to remedy this. I don't have the money to go out and buy a new Holley at the moment, and i also don't want to spend an hour or more tuning it before i drive it every time i drive it, being as it is a daily driver. Any thing that i may be able to do for this that doesn't require a new carb, or of not, a suggestion of a Holley with the secondary vacuum that won't require constant tuning to drive. My carter is like a set it and forget it. I tuned it once and i haven't had a problem since, except the weak spot.