While just fine for everyday transportation, the flathead needed a bit or ignition help to run at its best. First, add a little bit more tension on the distributor's breaker point spring. Adding another small spring is a good way to do this. There is a limit where the increased spring tension causes the distributor cam to wear down quickly, so just increasing spring pressure isn't the answer.
Still need more? Today you can switch over to one of the modern ignition systems with a high power coil.
But when flatheads were king, this wasn't the case. One step up is the dual breaker point, single coil system. This gives a hotter spark by increasing the dwell, or time the points were closed. Unfortunately, it only adds a few degrees of additional dwell, and is still cursed with the point bounce that hurt the stock single point system.
The next step is a dual point, dual coil system. This uses a distributor cam with half as many lobes as cylinders (4 instead of 8). It is actually two complete ignition systems inside one housing. This doubles the dwell time, so that the coil can produce a stronger spark.
Don't forget to tune the spark advance to suit the engine. Most performance systems offer vacuum and/or governor weight advance systems. For onlt full throttle use (racing!) the weights are the only choice because there isn't enough engine vacuum to run the advance.
If this still didn't do the job, you had to step up to a magneto, which uses permanent magnets to generate electricity and is run by the engine itself. This way, the ignition system does not require a battery. Unfortunately, this creates a problem - how do you start the car without a battery? So, the battery still had to stay.