How do you adjust valves on 1968 Chevy C10 inline 6?

remove spark plugs,

bump motor over till piston 1 is at TDC ( top dead center ) on the compresstion stroke. at this point both valves are closed.

adjust all play out of all cylinders at TDC .. but don't over tighen

now the all play is gone from all cylinders and theres even pressure on cam shaft

the final spec is 3/4 to 1 turns down. intake

3/4- 1 turns down. exhuast

turn to spec at TDC for each cylinder