I have a 1995 ford thunderbird LX 4.6L V8, I put in the Z-MAX at about 35,000 mi. and now I have 115,000 and it's stll going strong. I don't have noisy lifters, knocking, smoke emmissions or anything else, it runs like a champ. just for your info I put about 50,000 miles on in about 2 years. I think it works.