I have a few lifters making noise until well warmed up

jerry6 said
I always use a bottle of zddp with every oil change , and change it every 2000 miles , 80% highway driving cruising at 70 - 80 mph , no short trips .
What royal purple oil should I use , and would it need zddp added . The garage I change oil at carries royal purple XPR 10 40 , 20-50 and HPS 10-40 , 20-50 , I use 10-40 weight synthetic oil now .

The only Royal Purple I've seen is what AutoZone carries and it says it's fine for flat tappet lifters and I've read it has a good ZDDP package already. Sorry but I'm not a Royal Purple guru to know the differences between the XPR and HPS. Maybe check out their website and it'll say.