Got Shell 93 Octane and now barely idles 1973 Dart 340

Pulling about 12 to 13" of vacuum a little better, but might be on the rich side now. A little hard starting hot. I will readjust the A/F mixture and check the plugs. I wish on knew what cam was in it. The brake booster has a hiss now. I disconnect and plug its vacuum source and it goes away.