DAMN! same crap happened to me last year after i rebuilt my 4.7... It ran great for about 15min then it took a doodoo..
I had bought some H.O. cams from the dealer and the passenger side cam had to get shipped from somewhere in the east coast... I called them for the pin and they said it wasn't available. And the cam was on backorder indefinitely. So i took it to a machine shop and they repaired it for 40 bucks. The pin is pressed in. I looked locally for the pin but wasn't successful so we actually used a drill bit cut the shank and pressed it in and saved the cam. So far i have about 4k miles and it's running GREAT!
If i were you, remove the timing cover to double check the timing marks. I bought a new bolt for the sprocket as well. You can reuse the headbolts as long as they are not stretched. I also reused the head gasket