Rare Dodge Dart GT? Which engine is this?

RustyRatRod said
Exactly just as the rest of the car. It could totally be something "rare" as we've seen no fender tag. Being what it is over THERE really makes it somewhat rare already! But race engine? Nah. Thing about it is, Even a stock small block in that would give a GTO what for.

In terms of the fender tag, it’s been very challenging trying to decipher what’s on it due to dirt and paint that had to be scraped off. I can make out a few digits but nothing comprehensive. Is there anything I can apply to it to clean it up?