MPG build 360

Make sure you are using a well set up vacuum advance system with the right curve on the distributor.

Any changes that can increase torque at a lower rpm will help you keep your foot out of the pedal. Higher compression, good exhaust system, very good tune in the carb and advance curves.

To that end, I wouldn't even consider a single plane intake of any sort. Stock intake or a performer/performer rpm.

Headers will make a lot more torque at low and midrange rpms over any factory manifolds.

Get a wideband air fuel gage and tune idle, part throttle, and steady cruise for as lean as you can get it while running smoothly. This can be a balancing act between idle quality and fuel enrichment on tip in, you will have to play with accelerator pump quite a bit to make is all run right. If you tune for smoothest idle quality using the old school vacuum gage approach, it will be very rich at idle. Yes it will run smoother and sound better but it'll burn a lot more fuel, and make you smell like exhaust every time you drive.

Idle and cruise advance should be pretty high with the vac advance hooked up.