Just did 2 to 4 bbl swap car starts wont stay running please help

On the front of that carburetor you will have three vacuum ports. The large center port is generally used for the PCV. The small one to the left that is slightly higher goes to your timing/distributer. The small one to the right is either blocked off or goes to some automatic transmissions. Make sure all lines and plugs are sealed properly. Make sure you have the correct carburetor adapter plate for the performer 600 OR YOU WILL HAVE AIR LEAKS. MMG