Mopar Action 408 Build

yr is correct about the rocker shaft relocation
the stock LA rockers have a big wear radius so that part would work if the shaft was just moved back
not so much if they are moved up-unless they are using longer valves (which is a really great idea) as well as smaller dia stems
so you have to check the geometry
try a stock rocker and a 273 style iron rocker and map the dykem pattern on top of the valve
open, mid lift and closed with your valve lift
looks like they picked a master with the nose rolled over- lift limited- maybe to avoid contact with the keepers/ retainers and the stem seals or to make the use of stock rockers possible
one known problem with stock rockers is pushing the pushrod through the rocker with spring pressure and rpm but I've run stock rockers with more lift than that when I had to
what springs are they recommending- similar to stock roller springs? post up the spring pressures
if you run hollow pushrods and the lifters have oiling that would help with the pushrod/ rocker wear
If you go roller tip rockers you will need a b3 kit
that was the long answer
short answer is to ask B3 and do whatever he tells you
me- i'd mock it up with the degree wheel and dial indicator etc
do those heads use LA stock length valves or long valves
is the spring height stock or do you have room for some better springs
what's your stem seal clearance
spring locators
measure twice- cut once