I have a 1955 Mercury Montclair, with the stock 292. The engine has been completely overhauled. I have replaced the harmonic balance, which had some play in, along with the distributor. The distributor has been converted to electronic. the car has also been converted to a 12 volt system My problem is that with the timing set at the correct setting, timing advances 40 degrees. The timing has been set by vacuum, but the problem persists. I have tried everything I could think of to try and solve the problem, and have reached the end of my rope. At lower speeds, she is surging and bucking. At higher speeds, it better, but still runs poorly, and performance is very poor. If anyone has any solutions, or ideas that could help me it would be greatly appreciated. Thanks...Billy