Running rough when AC is turned on..

Hey guys.
I am working on my 74 Dart 318,all original (stock). I have given it a complete tune up (cap,rotor,wires,plugs ect). Set the timing to 10btdc.The car runs really well. When I turn the AC on the car runs kind of rough.It did the same thing before the tune-up.

There are no vacuum leaks.

Not sure what other info you would need.

Any suggestions why it runs rough with the AC on ?
Author: admin