Have to wonder what kind of 1/2 azz shop installs a new clutch without resurfacing the flywheel.30 years a a master tech and never did that since I was like 20 and had no $$$ etc.As for a diaphram we run them in our cars.Mine 20 years and counting behind my built 440.Sons in his built 360 truck has been in forever but just started driving this year when he got it out of storage.We run CF setups and never a problem Have installed them in other Mopars also and they work.Id say flywhell is the problem as that is what mostly causes chatter.