engine fired for the first time.... almost

[PKRWUD]

Okay, I didn't see anywhere that you could keep it running by playing with the throttle. That means it has to be getting fuel. You said it never ran more than 2 seconds, which is all it takes to use the fuel the pump provides when it primes.

You can't determine manifold vacuum if it won't run. Vacuum should drop when the throttle is opened.

You sound like you have a mess there, and rather than jump from here to there and back again, let's do this one step at a time. Try what I suggested, and see if it makes a difference. If it doesn't, fuel delivery is not the problem. That leaves air, compression and ignition, so we'll get to it, but first things first. Try grounding the fuel pump (you will hear it come on and stay on after you turn the key on) and tell me what happens.

Take care,
-Chris