Hello, Healeyphiles -
It turns out that I have two burned valves, most likely from motoring about
for too long with the valve clearances closed up. I took the head into the
shop today and when it was disassembled the burned valves were evident. I
would have expected the burning to be on the flame side, but it's on the
seats and the flame side was fine on all of them. My machinist has ordered
the necessary parts and I should be Healeying again by the end of next week
if the parts arrive expeditiously.
Looks like I'll be keeping closer tabs on the valve clearances from here on.
Thanks to all for your advice.
Havelock, NC USA