i have dual rochester b's on my 54/3100. it gives me enough power to run a 2.73 nova rearend with a s-10/ t-5 trans and 235-70-15 tires. as far as mileage i don't have a working speedometer right now. not lon ago had a working odometer and i got 12.5 on road and 9.5 around town, partly because of the dual carbs and misadjusted carbs, to rich. hope this helps. ron btw i also have dual exhaust.
