Interesting, I've done the same to mine but it's running the (original?) AMAL Concentric
. The jetting was way off when I got it and it still ran; man yours is so close! I did keep mine positive ground, although I'm still running points and condenser.
I'm keeping my fingers crossed for you that the new carb will run. Maybe something is plugged up in that Monobloc
? I noticed in the video a lot of tickling and fuel dribbling out when it would start.