unless you have a 90z with like 20 miles on it cause its never left a garage. The lifter issue will not be fixed by replacing them. Just use a heavier oil and that noise will drown out a bit if it is the lifters. What you have to worry about is "ping"-ing coming from the engine as opposed to the heads. That would be indicative of detonation, which is very harmful for the engine.
"Soap and a shop broom? Oh man, that's rough. Been there." ~Kenny "Eww. Is that what jail is like?" ~ John "+3" ~Guapo
Kickerzx- "heres mine! you can jam all kind of stuff in there if you really want to."