Dick,
I was able to sneak into your garage and snap a few pics of the Imperial heads right after you pulled them. In this shot you can clearly see the "hot" valves at each end of the head.
http://bos-engel.com/66newyorker/headsoff/2hotvalves.jpg
On closer inspection it's obvious that one of the valves is pretty badly
burned.
http://bos-engel.com/66newyorker/headsoff/burntvalve.jpg