Looking for better fuel milage

Info only: I gained 17% increase in gas mileage going the Projection route. That's ~20 mpg highway, 17 mixed. Another 2 mpg plus added performance when I swap back to 273 heads, but I take a real hit in >4800 rpm range.

Rough estimate of 2 year payback at today $4 + per gal pricing and 10K miles per year.

This is a 65 Bcuda, 318 +30, CDI, 2bbl TBI, Edelbrock Performer, CompCam 268, 4sp, 3.23 SG, 205/70/14. rwh