4bbl's don't always cost you gas mileage. When your going to the store to get bread, your only using 2 of the 4 barrels. So, in a sense, a 500 cfm would only be 250 cfm puttn around town, or cruisn 55 mph. The only time them 4's are open is when your foot is down. Jett'n is important too. A good dual plane intake and a 500 or 600 cfm 4bbl won't be a gas killer, unless it's jetted rich. Another option would be a spread bore, given real small barrels in the front (for daily driven), and whoppers in the back when ya need it...
