How do I replace the valve spring on 92 Che...

Valve springs are most easily changed with cyl head removed. However, You can use a length of closeline (cotton type) fed into spark plug hole, pushing as much as possible into combustion chamber, then GENTLY turning crankshaft by hand so the piston pushes line up against the valves. DO NOT CRANK ENGINE WITH STARTER OR TURN ENGINE FOR ANY REASON TILL THE JOB HAS BEEN COMPLETED AND LINE HAS BEEN REMOVED.
after inserting line, remove the rocker arm from the valve and use a valve spring compressor (the kind that looks like a top terminal battery terminal remover) to compress the valve spring. Remove the two keepers that hold the valve from falling through the retainer (use a magnet and small screwdriver for this) then lift the spring off the valve. Compress the new spring and replace in the reverse order, making sure the keepers stay in slot at valvestem top.Once valve spring has been installed, turn engine backwards to relieve tension on line you installed and remove all of lit from cylinder. Replace rocker, and adjust per specs. (usually 1/4-1/2 turn down after becoming quiet while running)
good luck