There is no reason to attempt to adjust valves on a running engine of any kind, 6 cylinder, V8, or any other style, solid or hydraulic lifters. If the engine has solid lifters, get it warmed up, shut it down, and use the companion cylinder method of establishing top dead center on each compression stroke. All 12 valves can be set with two turns of the engine and they'll be accurate- - - -no mess, and it's done right the first time. Adjustable hydraulic lifters are set cold, with the engine stopped, by anyone who understands basic tuning procedures.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!