Tractor Repair: 464 IH, correct valve clearances, compression stroke

Question
I have a 1977 464 IH tractor that is loosing oil around the head gasket, below the spark plugs. I plan to change the gasket over the winter but I was wondering what is the proper way to adjust the valve lash after you have removed them?

Answer
After everything is assembled on the head, adjust the valves on each cylinder while it is on the compression stroke with both valves closed.  Use a feeler gauge between the rocker arms and the valves, and turn the adjusters on the rocker arms until the clearance is correct.  Then turn the engine until another cylinder is on compression stroke and do that one, and continue until they are all done.  The correct valve clearances will depend on what engine you have, gas or diesel.