I had my car down the street to
www.422motorsports.com These guys are true experts and fanatics. I wanted to get the carb and distributor fine tuned, with the extra benefit of maybe squeezing a couple more MPG's out of the car. Rich at 422, told me to get rid of the double pumper with mechanical secondaries. He said to get a basic Holley w vacuum secondaries and he could tune it so the car makes even more power and get 4-5 more MPG's
I still have the double pumper on there for now and it is fine tuned and tricked out, but, if I can get significantly more MPG's with a carb change and not even loose any fun............