I had the bad exhaust valve on a 2006 Ranger PU. I bought the Dover heads and they only lasted 20,000 miles before I had another burned exhaust valve. Also, the gasket set that came with the heads are cheap crap. The intake gasket cracked and leaked after about 500 miles. Replaced with FelPro.

 

I am also dealing with this right now. I see people recommending Dover heads but I also read that buying a rebuilt head is only a temporary fix. You eventually end up with the exact same problem. Maybe it has to do with the quality of the metal in the head? What have others done?

 

a burned exhaust valve is a indication of a lean fuel / air mixture in that cylinder

try running a full can or 2 of seafoam mixed in with the fuel in the tank ( 1 can of seafoam per tank )

let the seafoam clean out any clogged fuel injectors as you use your vehicle