My 1923 T smokes like crazy out the exhaust. Been told it is likely worn valve guides. Yes? Need to pull the engine?
There isn't enough oil available in that part of the engine TO get up through the guides.
At a minimum you need rings and probably a lot more.
You'll have more of an idea when you take off the head.
The valves most likely will wobble around in the guides so you'll want to ream the guides a 64th over, get valves with the over-sized stems and have the seats ground.
Mind you you will have to pull the engine forward in order to get at the rear most guide.
Valves, keepers, springs and all that good stuff........
valves are a good place to start. If it fixes the smoke problem i would leave the rings for another day. You dont have to pull the engine for valves. IF you do however i would go ahead and get the rings sorted. also, installing adjustable tappets would be a great idea if you have the engine pulled.... its all a question of "how far do you wanna go?" I had this same situation and eneded up completely disassling the engine stripping off old paint, painted it and then replaced a few things. Also make sure your internal oil like is unclogged
My T used to smoke like crazy, especially when cold. It smoked to the point that it was embarassing, especially when the engine was cold! I won't lie, my engine is pretty tired and although someone was nice and bought new valves for me, the valve guides were shot and it still smoked just as bad. But as Craig said, there isn't much oil going up through the valve guides, so I didn't worry much about them.
I was certain that it was the rings, and I was running the old iron pistons and who knows how old the rings were? Finally I was motivated enough to replace them with a new set. I bead-honed the cylinders, installed the new rings, and guess what? No smoke! It was SO nice! To this day, my T still doesn't have the slightest hint of blue smoke out the exhaust, whether cold or warm.