273 rocker arm adjustment

lash at 0 tells me its a hydro. If that's the case, give it .045 preload cold (one turn) after you tighten adjuster and feel any resistance on a spinning pushrod (0 lash). Adjustables are nice like that. Flakes in oil isn't good. If I were you, Id take those lifters out, remove their pistons (lifter) and flush them in solvent.