i have a 67 mustang 302 , slightly built up msd.coil, and distributor, a 625 demon carb , platinum plugs set at 45 , gas mileage is about thirteen on highway at 60to 65 mph thinking of putting smaller jets in, i do a lot of cars shows that are a distance away any suggestion thank you for any help
That was it back in the day of $0.45 per gal. No one look for millage. If you want economy with performance got to drop in a modern injected engine. Or, as 68gt/cs said taller gears and maybe convert to the Holley TBI.
Step 1 is to properly tune the carb. Usually this requires some time on a dyno/sniffer at a shop, or some expertise and an air/fuel sensor installed in your exhaust. Until you tune the carb properly, you're likely to suffer driveability and/or fuel mileage problems.