People never knew or forget that the last rocker shaft LA's used pushrod oiling. All I can figure is they were anticipating the Magnum engines and were testing/verifying that doing valvetrain oiling like GM and Ford had done for eons would work. Lol
Funny you mention that, someone in another thread said I was going to ruin my engine having both pushrod and rocker shaft oiling from too much oil up top... kinda late to the party, lol
I would guess that could also have been due to recently acquiring AMC which used the same size tappets but with pushrod oiling, maybe they wanted to consolidate to one type of lifter/pushrod?