My car on the hwy gets 24-25 mpg with the a/c running. Has a LS-6 with cam, headers, 36lb injectors nothing fancy. Makes 404 RWHP and has run 7.68 on a drag radial with a 1.90 60 ft so it's not leaving real hard. TKO manual also.
I just bought a Magnacharger for it and I'm hopin for 525-550 to the wheels and maybe 6.70 or so
1971 RS TKO 5 spd LS6
1968 Z28 302 4 speed
1980 Z28 42,000 miles 4 speed
2002 SS sunset orange 23K