you got almost 2 grand to dump, get a gear vendors under/overdrive. my father in law has one on his 74 nova. 502 wild cam dart pro heads. 1050 speed demon carb. he runs 10.90s on all motor driving it 30 miles to the track on drag radials. he can run 10.5 trailered with slicks. he has 4.56's and with his gear vendors he gets 12-14 mpg highway.
check out
www.gearvendors.com