283 focused on MPG

unless your getting the parts free, use the money on the little extra fuel!

 

I have a 283 with a Summit "peanut" cam, 500 cfm Edelbrock, Performer intake, block hugger headers w/ flowmasters, HEI, 305 (416 casting) heads, 700r4, 350 9" in my '56 pickup. Granted that it's like pushing a brick down the highway , it gets 17 mpg at 70 mph, the same with a Quadrajet, the same with a 650 Edlebrock, the same with slightly different timing settings, the same with Vac advance to carb or intake. One thing I would recommend is insuring that your tires are properly inflated.