Lots of parts in that picture. Which one?
The one above the valve cover
Narrower description please…
Are you talking about the vacuum actuator?
I see valve cover, distributor cap, fuel pressure regulator, spark plug wires, vacuum ports, brake booster hose, A/C suction line, fuel line quick disconnects, and a few other things.
Looks to me like the fuel,pressure regulattor. It’ll still spray after the pressure is released.
Soooo, did you ever narrow it down to fuel or ignition when it doesn’t start or stalling out right after it starts???
And I think you used invisible ink to mark the part you are asking about in the picture…
But my spidey senses tells me you are asking about the fuel pressure regulator, but my crystal ball is out of order right now sorry…
There are probably illustrations here.
Put a red arrow on the photo pointing at the item you want IDed. Then upload the revised pic.
Or if you are slow like me, you can point at the picture with your finger or ink pin or whatever and take another picture and post that one… 
OP must be happy with vacuum actuator.
Me, pull that engine, drop in a 408 SBF and an 8.8 rear end.
Yes and someone is pulling our leg