New cam...loud clacking lifters. ???

comp cam extreme cams are known for there lifter noise ..they have very aggressive ramps that drop of quick. that is where the noise comes from > that is what I have been told .. I had a set in my 440 with edelbrock heads and it claddered real bad after 1500 rpm . even switched to adjustable rockers......... still........... with no improvement.
won't use comp extreme cams again !