1973 Plymouth Scamp accelerating/braking issues, please help

"When I first checked it out, it started fine but I noticed (after checking the oil levels) that the oil smelled like gas, the car need a new battery, new alternator, and fuel pump"

I've read here about a fuel pump failure (diaphragm?) that allows gas to get into the oil, so you may have a diaphragm that works intermittently and has fluctuating fuel pressure.

Just a thought.