Can your doctor hear a blockage with just his ...

It's true that older doctors were trained to detect problems through sounds, as well as odors and (ick!) tastes.  Many of them are quite good at it and may be better diagnosticians than younger doctors who depend on test results.

However, if you don't have confidence in his age or methods, you will never be comfortable without a second opinion. 

Given the fact that you don't mention if you have other medical problems and I am assuming that your doctor knows your medical history, I would think your doctor knows what he is talking about. However if you don't feel comfortable with the answer you got if it was me, I would seek a second opinion. Take a look at this web site from the American Heart Association and see what is written here because it has to do with your question.