Flathead V8 Engine Distributor School - Lesson 2
Flathead Ford V8 engines like for the ignition distributor to cause a lot of spark advance at lower speeds and loads.
Spark advance is the number of crank shaft degrees before top dead center that ignition occurs. At idle speed, initial timing is normally about 4 degrees top dead center. For best operation, that needs to quickly increase up to about 25 degrees.
The 1941 to 1948 Ford and Mercury distributors had as much as 22 degrees plus initial advance as early as 1200 engine R.P.M.
The 1949 to 1953 engine had more spark advance at light loads than did the 1941 to 1948 because the engine liked it. It had less advance at high speed and load (to prevent pinging) because the compression ratio had increased from 6.8 in the earlier engine to 7.2 in the 1949.
In the next lesson, learn how to reduce the tendency of your antique flathead Ford V8 engine to overheat