1975 Dart Sport - Alternator Issue?

I know this is an old thread - but I just had a chance to work on the Dart. Here's where I am at:

• I had the battery tested. It failed. I purchased a new battery and put it in the car. I ensured all battery connections are tight. I drove the car - the car died 3 times - all 3 times while slowing down at a stoplight.
• I was removing some extra's from the car(backup camera, gps, etc...), and I took a look in the engine bay. I noticed that there is quite a bit of stuff that looks jerry rigged. I noticed that what appears to be the ported vacuum hose is just hanging out in the engine bay - not connected to anything(see picture). There is no evap canister in the engine. Could this be affecting the engine performance?