Having had a bit to do with Petter PC engines, I can confirm that a PAZ1 injector holder will not be suitable. Early PAZ1 injectors are clamped in position with a bridge piece (much like a Lister CS). Later ones dispense with the bridge piece, but are still not suitable as the high pressure fuel connection is at a compound angle to the vertical axis of the piston. Hence if you tried a complete injector assembly from a PAZ1 engine in a PC1. there would be a good chance that the injector spray pattern would be wrong as it would not entirely line up with the combustion chamber in the PC piston crown.
IMHO you would be better to use a Bryce injector holder from a Petter PH or PJ engine, as they look very similar to the correct PC injector holder. Do you have the injector shroud or is that also missing? Both of these items are easily found on the likes of Ebay etc.
If so you may be able to use the same item from a PH engine, though you may need to modify it somewhat.
IIRC The injector shroud on a PC engine was turned out of copper bar, and was a real work of art.
The injector nozzle from either a Petter AV, or PH may be a better choice, as the combustion chamber design is similar to the PC engine (valve cutouts), whereas the PAZ1 combustion chamber has no valve cutouts in the piston crown.
Finally I suggest that you contact Jim Perkins, as he has a website for Petter engines, and may be able to help you with a source of parts.
I do have some used PC parts myself (no injectors or injector shrouds) from a PC2 I rescued from a scrapyard just for the electric start parts, and which I am now looking to move on, as I have no further need for these parts.
