depending on Head dia of the valve we have to set the Rotation of the valve, Stellite flow and Current
If it's got the original valve seats in it, I'd recommend using Lead Substitute in your gas. If you've got stellite valve seats, which by now you almost certainly do, unleaded is fine.
Many stellite compounds can't really be cut, only ground or abraded. I use stellite 100 cutting tools in a lathe, and they're made to cut, not be cut.
Stellite contain iron, cobalt, chromium, mangan, carbon, molybdenum, etc.
You will have to consult the manufacturer. A cast iron or steel globe valve could be trimmed (disc and seat) with bronze, iron, steel, stainless steel stellite, ceramic, rubber, neoprene, viton....or any series of different trims. The manufacturer usually determines trims by code numbers. Kinka valves indicates that this trim material on their valves is 304 stainless steel (13% chromium, and nickel content).
ileocecal valve
ileocecal valve
Ileocecal valve.
Spring loaded safety valve.
The exhaust valve runs much hotter than the intake valve, so it has to be made out of a more durable(and more expensive) material. The intake valve can get by with a simpler and less expensive material.
The only things unleaded gas could screw up in that engine are the valve seats. Volkswagen started putting Stellite (a very, very hard metal) seats in their engines in the 1960s, so you're fine.
This depends what shut off valve is in question here. Where the leak is and what type of material is the shut off valve made of.