.................and unless you want to mentally rework the timing marks and cylinder numbering on a Ford it IS useless. My point is, that chart IS great for (most) GM and all modern Mopars, not so much if you find yourself leaning over "something else."
Factory original 351s are NOT 1843 ......etc. The old FE/ 289/ 302 etc WERE if you rework cylinder numbering.
Newer GM is different, as well
AND...............if you have an older "original" 351W into which you've stuffed a "302" cam, you have to pay attention to "which" Ford Firing order is actually being used.
I don't need to know any of that, LOL EOIC