I don't have much to add, but ive got 273 adj rockers on our 340, solid lifter setup. OEM ball/cup pushrods, factory length. Zero issues.
I have a couple extra sets of push rods if needed.
Yup and you'll likely not have any. What I like about those ductile iron rockers is, If you want to go to a .650 lift roller, you got enough rocker arm to do it. They are tough as nails.