which carb do you have?

you said 2in vacume revved up or at idle---------which port------either way manifold should be higher at idle, less as revs/load goes up

Ported should be low or zero at idle but go up with r's

He can make the engine run much better by getting a dist with dual advance------think they maybe came out in 1958?

Also---check to see that the advance plate is moving in the dist-that old could be stuck