Since you have cranked the motor with the fuel lines disconnected you have probably determined that you have
fuel being delivered to the carbs if that is true,do you have spark? Just because you have all new ignition parts don't assume you have spark.Remove a sparkplug reconnect the plug wire and ground the plug to the engine block have someone crank the motor watch for spark(dont touch the wire or you could get a shock)if you have spark and fuel it should fire it might not run but it should at least fire.
All most all situations where an engine will not start involve the absence of fuel or spark (or both)A complete loss of compression is another reason.