LA /Magnum hydraulic roller lifters.

i´m pretty sure what you can get nowadays as replacements they are all the same - at least i could not find any difference. I did not see any LA HR-Lifters without the pushrod oiling hole up til now.

Regarding your other questions: i ran these up to 7000rpm without any hiccup, regularly up to 6800rpm. No trick stuff, just basic Performance Parts. Heads / Springs set up by IMM Engine.