I'm starting to think that replacing the phasers is a mistake without replacing the cam with a performance one. Comp Cams makes several that are great for these engines. You'd need to also install the phaser limiter too. I believe that most of the phaser noise is caused by an O ring failure, not the phaser itself. Replacing the O ring would be part of the cam replacement. From the failures I've been able to study, the failure is lack of oil pressure at the phaser. If the O ring fails, the phaser will run in a low oil pressure environment and won't advance like it should creating a retarded cam timing detonation we hear as noise. So if you are going to have the phasers replaced at yer expense, might as well get a performance boost out of it. And besides, you know you really want a cam sound with that exhaust system.