I know you can read spark plugs. Wondering if there's a similar technique for valves? Popped the heads on my flathead and noticed the exhaust valve in #1 looked grey. Basically a sort of "fogged" greyish white around the outside of the valve. I've heard before how the no. 1 cylinder sometimes runs lean and in turn gets hot, causes problems with soft header bolts, etc. It doesn't really look like it's in bad shape - but definitiely looks different than the other fifteen.
A burned valve has a notch or flat spot at the face (the part that contacts the seat), so it does not contact the seat at the burned part.
The valves in my Alfa Romeo motor actually turned black-they had a charred appearance and one was cracked with a chunk missing. Yeah they looked like the picture. I did see a set of burnt flathead valves once-similar appearance and the edges were crumbled away. A burned valve will eventually lose big chunks so if you have any doubt replace it.
Sounds like no 1 is running properly, and the other 7 cylinders are running a tad rich. Normally the exhaust valves will be white, grey, or tan, if the fuel mixture is right and the engine isn't burning a lot of oil.
I can live with this explanation. The rest of the cylinders did have a pretty heavy carbon buildup. I'll try to get pictures later.