Valve Lash Adjustment: running or not?

[bitfactr]

I have a stock '70 big block Chevelle with a solid cam. I've been pointed by reliable sources to several on-line references/forums that describe the valve lash adjustment procedure. While varying slightly, all agree that it is best to do hot, once the engine is warmed-up. All also said or implied it is done with the engine <span style="text-decoration: underline">not running</span>.

The couple 70's era repair/tune-up manuals I have both say the final adjustment should be done with the engine <span style="text-decoration: underline">running</span>.

Anyone know if the accuracy between running and not running is that significant?

Thanks,
Dennis