1999 Dodge 5.9 litre van

Burned valves were common in the '70s when we went away from leaded gas. Typically the exhaust valve on one of the middle cylinders on the right side would burn because when the engine was cold, the heat riser valve in the exhaust manifold closed to force all of the hot exhaust gas from the right side to go through that head, through a passage under the carburetor to warm it up, and out the left side exhaust. That system isn't needed to warm up the thermostatic spring for the automatic choke now that we have fuel injection.

Burned valves do still occur on any engine but it is very rare because of the better metal alloys they use now.

Caradiodoc