<VV> Diagnose engine "knock" ?

[Charles Lee]

I back to working on my 1967 Monza 110 PG that was "knocking" before it ran 
long enough to warm up.

I also had the gas "aroma" that plagued me even after the carbs were 
adjusted to be exactly what the GM manual specifies and according to Bob 
Helt's book.
The timing was spot on, too, but still she knocked.

I checked my compression to find 0 in #3, as I posted earlier (before I got 
distracted with a friend's overheated Saturn).

After thinking about my problems, they all seem to be related ?

My theory is that gas in the exhaust comes from the exhaust valves, which 
are hanging open because the #3 exhaust valve seat has worked loose, which 
has also been causing the "knocking" before it was warmed up.

So, my "knock" and "aroma" in the exhaust are all symptoms of the same 
problem ?

I'm pulling the head and it should be out tomorrow (Friday), but I'm having 
trouble with one pushrod guide bolt that pulled the stud out with it, and 
the pushrod tubes are stuck tight.

What are the odds that I'll find a dislodged valve seat on #3 ?

Charlie