Doesn't matter what the firing order is, unless you're firing two cylinders on the same bank one after another. And since no one does that, it doesn't matter..
Last time I checked my firing order It was 1, 8,4, 3, 6, 5,7, 2.. I believe all mopar and gm fire this way 8 and 4 on the right. 5 and 7 on the left. one after another. So now what? Does it matter now? You must have an X on your ride or are dreaming of getting one. X-pipes are a waist of money My car wouldn't pull past 7500 with an X. 9000 with and H and its right up against the rev. limiter It goes up so quick it sees 9300 on the recall with the rev set a 9000. X pipes are an intersection of exhaust interuption. Its a no brainer when two masses cross paths there is a conflict of flow. you idiots just keep believing what you want. I will never install an X on my Cars. Only on yours and as many as I can $$$$$$$$$