Well before you start paying out for adjustable regulators, you should work out whether that is your problem. Not that a regulator would hurt.
Presumably you have run the battery down trying to start it. If you have been pumping the throttle it will be flooded.
Fully charge the battery, and work through logically. If all you have done is bolted on a manifold with carbies, look back at what you have done and check your work.
Once the battery is charged, try again whilst holding the throttle down, but do not pump it. You are trying to clear out fuel mixture.
If it starts, it will likely run like a pig if it is jetted for a 2 litre.