625 or 750 for stock 340

wasn't a popular upgrade back in the day a 440 carb on the 340?

Yup. Since the AVS is similar to the Thermoquad, they are more forgiving. Although they don't have the small primaries, the secondary air door is still tunable enough to allow them to be used on a wide array of engine sizes.

BUT.....I don't think they are a bolt on swap. I think the 440 carburetor has larger bores and requires a spacer. I could be mistaken, but I think that's right.