gas mileage update!

OK. My dad says that he found the problem. Apparently the new Road Demon carburetor (4 barrel 750) was having a linkage problem. Basically, the progressive linkage stopped functioning properly and, even at partial throttle, the secondaries were opening. Not completely but enough to make a difference. This would also explain why the car seemed to have changed it's acceleration characteristics.

Basically, as I understand it, we'd push the pedal only very lightly but it'd be equivalent to half or more of the pedal. This accounts for the fact that even light-footed exercises in the car for testing purposes didn't change gas consumption characteristics.

Anyway, thanks for all the help. We're sending the Demon back to get fixed. Is this a first time hearing about a problem like this? You'd think that an expensive carburetor like a Road Demon wouldn't have these silly mistakes... Save those for Holleys, right? =)

Dang V8s... Nothing but problems.