FelPro has a timing cover kit , you will also need an intake pan 1214 for 383-400 B engine or 1215 for 413-440 RB
& probably valve cover gaskets
, the front cover can be removed & installed without dropping the oil pan , I put a bead of good quality ultra silicone between the pan & cover & istall the 2 bolt from the bottom to pull the cover down & tap it into place
the rockers are not adjustable Unless you go with a solid cam & aftermarket rocker arms which need to be set 1 at a time when the lifter is on the opposite side of the lobe