As you might expect the cylinder number scheme that Navistar/International used on the Power Stroke engine is odd. I’m sure they had some method to the madness, possibly legacy to older V8 engines, who knows. In any case it the same mechanical firing order as a Small/Big Block Chevy, but with the numbers for each hole changed. This is also the same as the T444E engine from Navistar (might be called other things as well). Note people use Powerstroke for all intents and purposes is the same as Power Stroke!

So if you want to cut and paste the 6.9L and 7.3L Power Stroke Firing order it is 1-2-7-3-4-5-6-8