What is the pistoncylinder order on a 1964 Mercury 390 ci and firing order?

The piston-cylinder order for a 1964 Mercury 390 cubic inch engine is numbered from the front of the engine to the back as follows: 1-2-3-4-5-6-7-8. The firing order for this engine is 1-5-4-8-6-3-7-2. This firing order helps ensure smooth operation and balance in the engine.