Motor shakes and has little power under load

My 68 Valiant with a slant 6 3.7 stalled on me yesterday. It took me a minute to get her to fire back up. Once it did start, the motor was very shaky and was running really rough. I was only a mile or so from the house, so I started driving it, but it would only go about 10mph. No power. Pinging like crazy. I know this may be vague, but you true Mopar guys out there may be able to narrow down what I may look at.