1998 Chevy S-10 Possible exhaust leak

One day my Chevy S-10 randomly developed this clicking noise. There was a slight loss in power but nothing major. Then I let a friend of mine drive it who didn't know how to drive a straight shift very well. He rode the clutch too long and revved up the engine way to far. I don't have a tach in it, but it was obviously red-lined.

Since then, that click turned into a full blown howl. It sounds very much like an exhaust leak. This was accompanied by a drastic loss in power, almost like it was only firing on 3 cylinders.

My dad said it sounds like a broke lifter, but that diagnosis was based purely on hearing it run.

I don't know a whole lot about car repair, but it is something that interests me. Since I've retired this truck and bought a new one, I figure this would be a good project to start on.

Any ideas on what the problem might be, and if so, where might I look for a way to repair this hunk o' junk?