[renaissance man]

I'm late to the game here but, wanted to chime in and get some opinions:
I'm running a '65 K-code 289, 4-Speed Toploader and a 4.10 rearend. I'm getting about 10 mpg. My car is running 4000 rpm at 70 (peak torque @4500 rpm) and 4400 rpm at 80 mph. Isky Racing Cam. Super fun and loud! Anyone think I should drop to a 3.73 or even a 3.55 since my 4th gear is 1:1 ?