Hi,
The firing order for a 351 and a new 302[ 5L H.O. ] are the same. The old 289/302 firing order has been arond for ages and the cams are a bit cheaper to put a jobber cam in instead of a 351 cam. That's it, money. The power and emissions are better in a H.O. / 351 cam, that's the reason Ford changed it.
Perry.
