This project is work in progress. Don't hold me to these numbers. My current numbers are not conclusive, however, at 5ATDC ignition retard setting I seemed to be seeing 10 to 12 MPG, at 7BTDC I seem to see improvement to about 14-15, maybe 16 MPG, if my gas gauge is working accurately.
Still pretty bad as compared to cars of today, but normal for V8 cars in 1972.

Once I settle in to a final advance ignition setting I'll try to get a more accurate MPG, but I feel it can't be anymore dismal then what you get at the retard setting. It might not be until spring, it's getting cold here in MA.