copper gaskets can be re-annealed and should be to reuse them. its a bit of a art in-itself, you heat it gently with a rose bud tip to temp around 400 deg celcius (or a dull red) and then quench in water this removes the scale. the reason for annealing is copper like all non ferrous metals work hardens. its not needed to re-anneal a new one as its already been done during manufacture. you can even do copper washers for banjo fittings too although at the cost of them not really worth it.

also a very good gasket dressing is hylomar or the coppercote gasket dressing spray from VHT products permatex has one too. i have used both and prefer the coppercote.

also i would pull a couple of bearing caps and see what there like they might be fine. drain the oil check it for water if it has water in it dismantle the oil pump and clean it.

like mike suggested scotch bright and kerosene clean off the scale and see what its like a hone may be all it needs.

Mike wrote:

That number stamped on the block, suggests to me that engine has been worked on at some stage in its life, I have a engine here stamped in a similar way, I think they are workshop repair stamps, perhaps the head was pulled for a valve grind, or a full engine rebuild. Keep in mind your tractor is over 80 years old, and might well be on its second or even 3rd set of cylinder liners, and piston rings, and valves, unless you know the full history of that tractor, assume it has done a lot of hours.
 

Thanks for that bit of info Mike. My D8 has a number stamped in the side of the block in a similar location but no serial number tag.