[dtmerritt]

In 3 weeks my wife and I fly to Alabama to pick up our "new" 1955 stock Pontiac Star Chief, V8, Auto with all the 55 goodies. I have not been able to find an mpg gauge for cars before obd II.

As this vehicle has a Carter 4 barrel on it I remembered from long ago that the idle circuits affect quite a bit of the power range I will use (I expect to drive 50 all the way back to Arizona, with some visits in Texas.) I checked the service manual and found I was correct. In the days of my youth we set the idle for smooth idle and takeoff (gas was +-.20 cents.)

I know I will not achieve 96 mpg, but 1 or 2mpg improvement over 2500 miles can help. I can get an oxygen sensor and adapter for the pipe, plus a air fuel gauge for about $30 on eBay and install them before leaving AL, and adjust the carb until I get a good lean, drivable vehicle.

OK, here is where I need your help! I know manufacturers set the mixture at 14.7 for the catalytic converter, which I don't have. I know leaner ratios are better for mileage, but without running too lean, what ratio should T strive for?