Ran for 45 seconds like a champ... Then this.

 

Did it shear the alignment pin??

Is the cam frozen, or can it be turned??

 

It did shear the alignment pin. Any tips on getting that little guy out of there? The cams turn but not sure what would have caused it to lock up and break that bolt.

I dont see anything under the valve cover that looks off, do you? What is the torque spec on those cam caps?

 

So the cams will still turn but they are TIGHT compared to the left side and of course to the core.

The left side will "snap" past the exhaust valve springs just like the core motor but this right side is so tight that it will not snap forward.

I wonder if one of the cam caps or bearings is bound up?

 

Pull a cam cap off and see if it's oily in there. And check for galling/damage.

Possibilities:
- Someone mixed up the cam caps and put a mismatched set on, they are NOT interchangeable
- I'm not sure if it can happen on a 5VZ, but on some cars it's possible to put a HG in wrong and block off the oil flow to the cylinder head. Dry bearings, they're gonna seize

There should be some more oil in the head after it's run for 45 seconds, I'd think. The lifters have little 'tubs' to hold oil in a little pool for the cam lobe, looks like they're pretty dry,.

 

This ^^^

Figure out why there's so little oil in there, and you may well find the trouble. Once warm, Toyota engines have very low oil pressure, but revved a little or when cold, it comes right up, and should have filled that head up with lotsa oil...
Oil pump, maybe...possibly?

I'm no mechanic, but that head looks awfully dry to me, for what it's worth. I know that aint good for engines, of any kind.

Good luck to ya.
​​​​​​​Pat☺