BIG CLUE here.
Foot on the gas steady = throttle partly open. It wanted start with more air available.
There is a world of difference between the factory automatic choke and whatever is on the Holley.
You'll have to feel it out. I'd open the Holley choke and start it without. Add fuel by pumping the gas bedal a few times. You'll see pump nozzles shooting fuel if you look. That's plenty. No need to pour more. Probbaly too much already,
Well that says (a) there's a ton of fuel-air in the intake. (b) spark fired while the corresponding intake valve was open.
Yes. See above.
One possibility is you tapped the vacuum cannister while changine intakes. That could have slightly rotated it.
Also, if the Holley has an electric choke and the factory did not have an electric assist, some mistake could have been in how the electric choke was wired in.
