I went into PepBoys a few years ago and asked for a particular spark plug number. Well, the kid behind the counter couldn't just give me the plugs...he had to know the application
Ok ,time to F... with him Told him it was a 540 Ford. Well , he couldn't find it , duh. So next question "what year"? 1999. Finally after about 15 minutes and not being able to find it , I told him it was a boat and just give me the plugs. Well all that and he didn't have them anyway
I never had the opportunity to tell him it had TrickFlow heads too
I know NAPA has a lotta stuff. And what they don't have , they at least have access to. Nearly all the bolt on accesories on my 540's came from NAPA.