You can put new lifters on a used cam.You just NEVER put Used Lifters On a new cam. One other thing you may want to do. Is scribe a line at the base of those rocker studs. This way you can see if the studs maybe pulling out of the head. This can cause the lifters to become lose and make noise.

Larry/Twisted6
[oooooo] smile
Adding CFM adds boost smile
shocked God doesn't like ugly.