My son (he's in San Diego Area, I'm in Salt Lake, so this is a long-distance deal) has a '66 122 making a lot of noise. Here are the specifics so far (the engine being turned manually):
1. It's at about the level of the crankshaft - an approximation. Maybe it could be close to the cam - it's hard to tell.
2. It's a sharp slapping noise.
3. It's most pronounced when the spring for valve # 4 is fully extended.
4. The same noise comes with a similar situation with one of the front valves (I can't remember which one he told me).
5. Removing the rocker arm assembly and pulling out the push rod doesn't change the nature of the sound.
6. The push rod looks cruddy, but looking into the head through the hole the pushrod comes through doesn't show anything useful.

Does anyone have suggestions about what to look for first, and how to go about fixing the problem?

Thanbks for the help - in advance,

Jim Hampton