Originally Posted by RTM
i was always told that the 351w reduces the load on the front of the crank snout because the firing order is not 1-5 like on a 302 engine. not sure how much merit this carrys but it always sounded like a good enough reason.
It is my understanding that this is why Ford changed the firing order ... better bearing life.
I doubt it makes any difference in performance or idle quality. If it does, you'd need a dyno to tell the difference.
The only real draw back to going to the 351w firing order, is that your plug wires won't fit any more. If you're replacing plug wires, though, there's really no reason not to go to the newer firing order.