Reply to "valve adjustment questions"

FWIW, I hot-adjust my engines while they're running. Slide a feeler gauge between the rocker wheel & valve stem while manipulating an allen wrench for the internal setscrew. Follow immediately with a box-end wrench to lock down the setscrew about 1/8-turn, as humans cannot tighten the setscrew tight enough to hold more than a few seconds. Tightening the locknut will change the lash, so you can see this isn't easy to do "perfectly". It may not matter much, either.

A story: many years ago, a man invented a dial-indicator attachment for perfectly adjusting valve lash, and showed up at Ed Iskenderian's So-Cal race shop. He pushed Ed to endorse his invention. Ed had a Chrysler engine on the dyno, so he invited the guy in for a demo. Ed told his mechanic to "run the valves like we're at the track with 10 minutes between rounds. You know- kinda sloppy". Then they dynoed the motor.

Next, Ed let the inventor use his patented attachment & tools to carefully set all the valves; took him much longer. The next dyno test showed a LOSS of 50 horses. "Perfect adjustment" might not be what we need on old-school engines. The invention never sold well & the guy went out of business shortly thereafter. You still see the invention on E-Bay now 'n then.