Just got the 170 in the wagon running after fifteen years. Bad rocker valve adjuster, gonna tap, thread, and Allen plug in place like old drag FE's used to do.

But, with pressure, two of the large core plugs (three on passenger side of block) started protesting in retirement. Swapped. Replaced all three. And sure you know it, I bolt exhaust and manifold and accessories back up a new core plug I didn't see started cryin down on the starter. About 3/4"? and underneath cast manifold on head above number five? How many more are there? The factory manual says nothing about them. Chiltons ditto. I'm on guesswork here. Any body out there know what I'm in for?

Thanks!!