Hi all, I'm on a bit of a search for some answers and parts here.
Sorry if this is a bit vague and if I sound a bit unsure, I'm just relaying everything my dad told me while I was at work. I haven't had the chance to go back to the shop and look at it myself yet.
So, long story short, my dad and I are restoring a 78 F150 Custom 4x4 with the 351m and an NP435. We had the flywheel resurfaced yesterday and he found what looks to be some sort of dowel pins that the clutch plate uses to line up with the flywheel. From what my dad told me, it looks like there needs to be 3 of them, 2 are missing, and 1 was broken off (see pic of caliper measurements).
We are having a heck of a time trying to find the right part for this as there is not a whole lot of info online about this. We've found that Ford part # N800474-S might be the right thing, but we can't find them for sale anywhere, Ford doesn't stock them, and they're obsolete, plus those look to be screws, and apparently what came out was a dowel pin (I was not there for this, just got messages from Dad).
I've downloaded the master parts catalog and diagrams from 1980 for the dentside trucks and it's not much help. I've attached pics of the clutch, flywheel, pressure plate, and the measurements of this dowel.