Don't know about the RPM range but I do know that one of the members here works for a Mopar dealer (Mopar Super Center?) & they had the Comp Retro-fit roller lifters listed for almost $100 less than Summit. Also, I have a Comp roller cam. I called them & they told me that I didn't need a bronze gear with it. I'm still a little leery of that info & plan to double (maybe triple) check with them before I assemble my engine.
