Fuel Economy Help

any 1 5/8" primary header will help some with mileage if you can keep your foot out of it, a shorty header will probably be your best bet. also experiment with the different grades of gas and your advancing the timing as much as you can before it starts to ping and you can also experiment with different jetting and power valves on the carb depending on what carb you have. i would set it as lean as possible again as long as it does not ping. beyond that the only other things i could suggest would be taller gears, overdrive trans, taller tires and then you'd get into engine mods, like better heads, more compression, different cam timing or even a different cam altogether.

Make sure your tire pressure is correct (that it is high enough). I put in a five speed in my car, and I can enjoy performance gears(3.89) and overdrive. I am thinking about putting on taller wheels and tires(mostly for style and handling reasons, but I can justify it to myself by thinking about milage!).

with the right cam, carb, headers, and even heads you can get pretty decent mileage. you can get even better with an od trans and enough gear to launch the car without having to slip the clutch. my recomendations;

1: a comp cams he260h or he268h cam.

2: an edelbrock performer intake(works great with the above cams).

3: a set of tri-y headers with 1 1/2" primary tubes.

4: an autolite 4100 4bbl carb(the 1.08 model).

5: when you can afford them, a set of windsor jr heads.

6: a T5 or aod trans with 3.50 gears.

this is a mild combination for a daily driver that when driven right will surprise many people, and still deliver about 18-21 in town and 25-27 on the open road. my last combo for my mustang was a stock 4bbl intake with the 4100 autolite, 4-1 headers(1 1/2" tubes), 2.80 gears and a 3spd trans. the cam i used was wrong for the combination, and i still knocked down 18 city and 25 highway. my new combo should reach at least that level with little problem, unless i go overboard and build a healthy 393w