6. If you are ordering a new cam for your engine, you might want to consider a cam that has a 4/7 firing order swap. The number 4 cam bearing has extra load put on it because the number 5 and 7 valves are open at the same time. Also, since 5 and 7 intake ports are next to each other, when the number 5 cylinder valve opens it disrupts number 7’s intake charge. The swap cures these issues and makes the motor a bit more efficient.