I averaged ~15 mpg (318, Edelbrock LD4B, 1406, auto., MP electronic ignition, Flowmaster 40s (stock manifolds 2 1/4" pipes), 3.23:1 gears in a sure-grip 8 3/4" (with P215/75/R14 rear tires)). Speeds were 65-75 mph as some guys were running 3.91 gears (I was turning about 3300 rpm @ 70ish mph).
