im quoting this so people will read this and laugh about how absurd blaming a "bad valve stem seal" is when talking about why you lost a street race.
I will take your perfectly running car, dyno it, then i will remove every valve stem seal you have, and we will redyno it, and $100 says the power is negligible in difference.
i know because ive had crushed valve stem seals, because i ran PRO3s, before anyone else did, because im THAT baller
EDIT: ive met more techs with ASEs that i wouldnt let come near my car. Just walk into any dealership