Hy Adam61, the only things i can think of which cause the lifters to make onise are, a lack of oil to them, loose adjustment, and part wear [cam lobes, lifter bottoms, rocker arm pivots], sometimes the rocker arm adjusting nuts don't hold their adjustment, they become too loose. Are you sure it's a lifter noise? Check your harmonic balancer, they can wear their key way and hunt back and forth, most 283 balancers were not retained by a bolt and can work loose, hope that helps.
