I've got a nice set of the old mechanical six-pack holley carbs. After exhaustive research on the subject, its nearly impossible or not practical to convert them to the vacuum set-up as they were never built for it. With a stock cam and no headers on a 440, is it possible to use these carbs with decent driveability. Mechanical secondary anything has never been my choice for a driver, but this set-up is a little different. Any thoughts?