I have a 50,000 mile bone stock '69 383 Roadrunner. Even with the AVS, it's way under carb'd. I bought the car with a Holley vac sec 750 on it and tuned it best as possible before I found and installed a correct date coded AVS. I spent a lot of time dialing in the AVS and even then, there still is no comparison. The car flew (for a stock 383) with the 750. Not sure why but it seems other than the factory multiple carb set ups, Mopar under carb'd the 4 bbl cars until the T-quad came out.
