What's good mpg for 1966 315 hp 390?

[schnook64]

I have a 1966 hardtop with the 315 hp 390 engine. I recently installed the Petronix electronic ignition. Everything is running very smoothly but its really sucking up the gas. I'm new to this car and don't really know what I can expect fuel efficiency-wise. Its been difficult finding info about it too! Any ideas?

[Dirty Birdy]

One way to figure out just how well your car is running (other than the seat of your pants) is to put it on an exhaust anilizer. Most of the larger shops have them for emissions testing. They stick a probe into your exhast tips and receive info on things like CO, CO2s ect. These numbers will tell you if your car is running too lean or in your case, if its running rich. You may find that its running too rich if your really going through the gas.

[schnook64]

Thanks for the tip! I'll have the shop check out the emissions and look at the carb setting too. I've filled up since and the Bird turned out to be getting about 11 mpg with all city driving. That was a nice surprise.