Maybe Paul Kane our resident 460 guy will see and post, but in the meantime, I have a 460 that I used Harlan Sharp roller rockers on. Has screw in studs and guide plates. Been a while since I did it so not sure about pushrod length, but mine has a roller cam anyway so it wouldn't probably be the same. You will probably want to do the geometry once you get everything setup anyway,so your pushrod length will be determined then.

BTW, welcome to the forum.

Don