Engine no longer starts

Hello together, I signed up here to get some helpful tips. The following problem has occurred: My ignition distributor was not the best anymore, the contacts and distribution connections were already quite rammed and the cold start behavior from the engine was more than miserable, because sometimes I had to start until the battery was sucked off. So I bought a new HEI distributor and that was the MSD Pro billet, because this supposedly a very good cold After several attempts, false ignitions, stab flames as well as fumes from the carburetor, we were able to set at least the correct ignition sequence and correct ignition time. Now it seems that the engine does not get enough fuel from the carburetor. He wants to ignite and you can hear it that he wants, but there is nothing. Spark plugs were also a bit too damp. Can it be that we have scrapped the carburetor (Street Demon 1901 / 625 cfm)? Motor is a 5.7 L / 350 automatic with allegedly larger pistons as well as sharper camshaft according to the previous owner, but I can not prove it and also at Downtown Garage in Berlin they could not tell me anything about the engine. Maybe one of you knows the problem. I am absolutely no expert and rather a Newbie.