Considering that I have no leaks, water jackets are not full of goo and most importantly that I am in Malta and would have to get replacement plugs ordered, would you change these? I don't have experience in how these should look like.

Also can someone tell me what that dime like thing is on the freeze plug. I have two of them on the side freeze plugs furthest back.

I think they are good to go. Leave them in....

Hard to tell their interior condition from the outside, but they look pretty good.

The bottom photo - it looks like it reads, "Marshall - Do Not Remove".

I wonder if it's the way an engine builder would ID their work?

Edit (FWIW, if this is a rebuilder's ID):

http://www.autopartswarehouse.com/sh...l_engines.html
http://www.newgmparts.com/marshall-rebuilt-engines

Internet search returns some links that Marshall engines and Blueprint engines are one in the same.

However, I don't know if there are more than one company that rebuild engines that call themselves, "Marshall".

In the meantime I managed to find out those Marshall what they mean

Apparently they are wax glued pieces which would melt if the engine overheats thus voiding the work that was done on it.

Right: those are a "telltale" for overheating. The motor has been "rebuilt"; the "rebuilder" would not honor any warranty if they have been melted.

If the block is torn down, replace the freeze plugs. They rust from the inside, and can be literally rusted through to the point of paper-thin and ready to pop the very first time you start your "new" build, and still look perfect from the outside. It's impossible to know what condition they're in by looking at them from the outside since that's not where they go bad.

Their rust condition does not care about your location or "order". They are not listening to sob stories. They either will fail, or they won't. You have no way of knowing.

Since the block is torn down, replace them, so that your next post isn't something about "I just put this new motor in my car and water is pouring out from somewhere between the engine and transmission, how can I fix this without pulling it back out?". Put in brass ones so you never have to worry about it again.

Thanks for your opinions. Will consider your view sofaking but if the engine has been rebuilt at least once in its 30yr lifetime based on the Marshall stamp on the freeze plug and the fact that it is bored 060 oversize I would say they shouldn't fail anytime soon.

Will think it over.

Thanks anyway.

Damn, Sofa took the words right out of my mouth. A set of plugs is dirt cheap and they're a major pain to replace in the car. Change em.

Just do it.

Going to order a set. Another delay waiting for project completion

Will order brass ones as sofaking suggested

Better to wait and do it now then to have to wait and do it later.

I followed your opinion and went ahead and removed them . Not that I am sorry but the plus didn't have a hint of rust on the inside either. At least I get to clean up the water jacket a bit better and will also put copper ones as apparently it is better. can't understand why as I think steel are there for a purpose which is for them to rust instead of the block but I may be wrong.

See pics below

Sorry don't have one clean in the picture. Will take another one later on.

Thought it was going to be easier to order. Rockauto site lists 1.625,1.638, 1.640 & 1.643.

Should I simply measure the ones I removed or is there are other school of thought?

Just get a set from Summit or something. Same set fits all SBC motors since around 1959.

Their actual purpose has nothing to do with freezing... it's actually to let the sand out at the completion of the casting process.

Understood. I always thought that they also served as a sort of sacrificial anodes

Will get a set from rockauto then.

Thanks guys

Interesting thread on an uninteresting topic.

Interesting bit of trivia about the wax disc overheat indicator.

Yeah the overheat indicator is VERY common in cheeeeeeeeeep rebuilt motors in the US anyway... THIMK, the kind of person who would buy the cheeeeeeeeeepest "rebuilt" motor he can find, is also the kind of person who needs a motor precisely because he burned up his old one by neglecting "costly" cooling system maintenance like the rad cap or even just keeping it full of coolant. The "rebuilders" who serve that market have to protect themselves from those idiots somehow.

Yep , even though they may pop out when a lack of antifreeze in the coolant allows it to freeze , by the time they do pop out the block is plenty trashed . Folks seem to have a notion that the "freeze plugs" will pop out first and save a frozen engine , but anytime I've ever seen an engine suffer freezing to the point that the plugs popped out the cracks were all through pretty much every part of the block's coolant passages , in places where no "freeze plug" would or could have saved anything .

Make sure the bore of the freeze plug is clean and smooth on the block, I smear a dab of silicone around the plug and drive it in with a big socket.

Yepp that's what I will do. Some RTV perhaps.

The plugs have been ordered. Decided to go steel last minute as I will surely be using proper coolant and I don't like the idea of having brass which is a bit harder in terms of material and with different expansion properties.

Well, brass is better for a number of reasons, but steel is still perfectly OK even if not "the best". Even though brass is softer. The fact that brass doesn't rust, which is the way steel ones invariably fail, is golden.

I prefer to use some sort of hardening sealer on those rather than RTV, like the purple stuff in a can from Permatex/Loctite... sand both the hole and the plug in the circumferential direction, put a little both on the bore surface and on the plug, tap the plug in with a large socket that fits inside the plug fairly closely (be careful though, that it doesn't fit SO tight that when the plug is crushed inward by being driven in, that you can't get the socket back out of it), drive it in below the start of the hole (about 1/16" farther than those were in the photo), wipe around the outside with a finger to make sure there's a bead of sealer completely sealing the edge of the plug where it meets the hole.

Will try to find the sealant that you are referring to.

Thanks