496 firing order
 

Why did GM change firing order from lifetime of 18436572?

Isn’t it to make them smoother/more efficient?
Think the 8.1 is a double swap from the traditional GM.

Reduced crankshaft torsional vibrationwas the main reason GM adopted the engine's 1-8-7-2-6-5-4-3 firing order. According to GM engineers, computer modeling showed that the new firing order improved reluctor wheel accuracy and eased bearing loads. Minor power gains are associated.