I've seen some prior discussions about how much slack there should or shouldn't be with a timing chain, but I'm wondering if a chain can wear much in 4,000 miles. On my SBC, ZZ4 crate engine, I can move the chain about 1/4 inch side to side, on one side only. Normal? Or shall I replace it? Not familiar enough to know if a new chain will have the same movement. Thanks for any help.