This post started a long time ago--and yes I was not happy with Comp at the time--found out that the Morels work, have been using them ever since and have found out more about them--the Morels like max spring pressure of 140 seat and 350 open--they like a quarter turn pre load--I have run more but...they seem to be able to handle about 6000 RPM but more than that and you risk valve float quick! As time has passed more hyd rollers are coming out that can take more spring pressure, are valved different and thus can do more more RPM--I have used them for Chevys and Fords, so far none for Mopar that I can find.
Take care with spring pressures and use as little pre load as you can get by with and the Morels are the only game in town.
I was ranting about Comp a little too hard at the time but remember I had two customers with issues directly related to the sorry lifters I had from them.
IMO the lifters are heavy, this and inability to use higher spring pressures greatly contribute to the RPM limits I have observed.