Rebuilt Carb causes "chug" "chug" at ignition

[trndkll67]

So I recently rebuilt my Edelbrock 650 on my 67 mustang and renistalled. It started once, ran a few minutes and cut off. On the next few tries it gives a "chug" "chug" , kinda like its gasping for air. There's plenty of fuel getting into the venturis, so maybe it flooded. Not quite sure. I did have to alter the float height to meet Edelbrocks recomendations; maybe that wasn't a good idea since the car ran ok before.

I reset the idel mixture screws(tightened and backed out 2 full turns) but its still having a problem firing up. Anybody have any quick advice? Should I just pull it off again and recheck the floats?