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.

Thank you all for the advice. We have since found ourselves in a position to take the motor out completely. We are actually prepped and ready to do so this weekend.

The biggest problem is the pitting in the head and valves. It looks like new seats were installed at some point. If I could find new seats and valves it could probably be salvaged. I don't really even know where to look. I called FTP and no luck. I would even buy a used D4400 head if I could find a decent one.

I posted it on youtube

depends how deap the pits are if inside grinding range the valves can be reground on a W&B valve grinding machine and the seats can be recut any good engine reco shop can do this work. they should also be able to fit new stainless valve seats if they can get ones of suitable size same with the valves. you probably wont get a listing for the specific machine it will have to be via measurements. the fun is finding a shop willing to spend the time getting the measurements and cross matching.

i wonder if anyone has that factory spec data it would make things easier.
try your local engine reco shop they might be willing to help or know someone who can. also try the local vintage and veteran car clubs they probably would know of someone who could do this work.

Valve seat inserts are 1-7/8 x 1-1/2 x 1/4 (Cat part number 1H230 for both intake and exhaust)
There are specification for valve seating and projection.....
 

just what the doctor ordered. thanks OM that should help him.

That is definitely a problem. The pits are very deep. Everyone I called has enough work right now to last a few years. 
Now I wonder if we just wait for a shop or wait for a head to come up for sale. I am finding that just about anything for a D4400 is nearly impossible to find.Its a shame, the rest of the tractor is on great shape. The rod bearings look great. 
Sad that a ,10 cent can over the exhaust could have kept the poor thing from so much internal damage.

keep looking you might find something or someone

I will keep looking. The factory valve data will really help! I imagine that if I can find some valves a good machine shop could find or make the seats in need.

You could also look for a D4600 engine as they use the same parts, only 2 more cylinder.

Regards