Spark Plug Seats

[Anonymous]

Our '68 200 was rebuilt a few years back, but continues to foul plugs 3 & 4. While removing the old spark plugs, I noticed that several had become very loose. Upon further inspection, I could see that the spark plug seats are square, not tapered like the spark plugs.

The code stamped on the 'intake manifold' of the head says C7DE-6090-A so I assume it is the right head. Are square seats for tapered plugs right for this era six?

 

[page62]

Ummm...no.

That sounds like a machine shop fix; ie. pull the head and let them fix it. Fortunately, it isn't all that hard to pull these heads...

 

[66 Fastback]

I think you need the plugs with the square shoulders and compression washers. Last year I pulled the plugs on a Pontiac I had bought and 7 of the plugs had tapered plugs, several of which were loose. The one cylinder that takes a contortionist holding his tongue just right still had a washer type plug. The head was meant to have the washer type plugs.
Doug