I missed seeing you at the NATS, but I guess you saw me leaving. My 75 Doba has a 360 and swap meet intake/4bbl, (there when I bought it) and was getting me around 13mpg. I put on dual exhaust and got just over 10 driving to the NATS. I got to looking and found that the swap meet intake is single plane, I never noticed it before. I'm on the look for a dual plane intake now. I'd be happy to be getting mid teens but I think there's more there. It has just over 70K miles and has lots of oil leaks and needs valve seals.(winter project) I'm intrested in following this thread to see what I can glean from it. Best to ya, Tony.