Slant 6 Aluminum Performance Head

The head isn't aluminum, but I'm gonna just leave this (decades-old) ad on the bar; thread with much more pics here.
The fail there is that the reverse flow head doesn't have pushrods in the way to start with, and most gains in lightweight valvetrain comes at the valve, not pushrod/lifter.....like 95/5% but that is a fascinating vintage gem of a nugget You dug up there! Awesome, Thx again Dan!!