1975 Eldorado 500 cid engine expansion plugs locations

[tiugu]

Hi,

This is my first post in this forum and I would like to thank each and every participant in this forum. I have found useful information in almost every thread.

I'm rebuilding my new hobby car engine ans since I could not find information about expansion plugs locations from shop manual or from any thread in this forum, I decided to ask myself and get clear where are all expansion plugs located in 500 cid engine.

There are 4 different types of plugs in expansion plug set.

1 larger plug in the rear of the engine, so called camshaft plug.
6 medium sized plugs for engine block water jacket (3 on each side).

Questionable for me are 3 small threaded plugs. I found two of them in the rear of the engine (seems like oil galleries) and one on sop corner of block in front. Are these locations correct?
There are also two smaller non-threaded plugs. I found two smaller plugs in front of the engine behind timing chain cover and two in lifter valley. So I'm puzzled which ones should I replace.
It seems like plugs behind timing chain cover in the front of the engine are plugs for oil galleries, but I'm not entirely sure.

Thanks in advance!
Best Regards,
Margus
Estonia

[TJ Hopland]

Some kits could include plugs for 'smog' rails in the heads.  A set would be 4 plugs on in each end of the head but originally 2 would have came with plugs so I could see someone maybe selling just 2.    I can't remember if they are the size of a US dime (18mm) or nickel (21 mm).