[100IH]

Model A's don't often have problems with firing order because of the original cap has the order built in to it . Since you have a Mallory distributor, you must have the more common cap and wires. Know that the order is 1-2-4-3 in a counter clockwise rotation. I agree that you should do your own compression and leak down test. Any distributor cap could have issues that can cause misfire. Good Luck.