64 Dodge Dart 270 parts wanted

I may have a motor found but I cant make out what this issue would be. Read the quote below of what the seller sent me in a email and voice your thoughts.

"I just took the head in to be redone. The shop milled the head and replaced 2 exhaust valves. I am having problems getting the rockers run and I can not get the miss out of the engine. The miss was not there before the head was rebuilt."