are they making the clatty noise?

are the pushrods too short?

using adjustable rockers? are you using the wrong pushrods with the hydraulic cam?

or how about more info?

Tony

70 AARCuda Vitamin C
71 Dart Swinger 360 10.318 @ 128.22(10-04-14 Bakersfield)
71 Demon 360 10.666 @122.41 (01-29-17 @ Las Vegas)
71 Duster 408 (10.29 @ 127.86 3/16/19 Las Vegas)