Why are my distributor cap terminals burnt?

Sounds (and looks) like you have a phasing problem. As rpm increases and timing advances the rotor moves further and further away from the pin on the cap it’s supposed to fire to. Until it jumps to the next pin. Which is why the terminals are burning, the gap is too large and why it runs like ****. With 22 degrees of mechanical, set your initial at 14 and lock it down. That’ll be 36 total. Then work on phasing.