Not mine! 2001 C-15 still smokes the pipes! It is freaky to see the pipes on the new trucks....shiny chrome insides and out!
As someone who has built his fair share or race and street engines. there are a few different opinions out there right now. I'm a firm believer in a high zink Mineral oil for break in on a street engine flat tappet or otherwise. There are several different companies that make specific break in oils, and break in additives all are very similar. The need for a high zink oil goes up drastically with valve spring preassure. If you are running 80lbs on the seat spring you don't need near as much as a 450lbs on the seat race motor, although you'll be hard pressed to find a race motor that isn't a roller motor. Break in on a street engine I normally suggest is any where from 8-10,000 miles before everything is well seated and broken in. Race motors on the other hand are far more accelerated when it comes to break in. A couple pulls on the Dyno and she's good LOL. There are many race motors that are running synthetic right from the start with no trouble at all. It all depends on the application, Mainly piston ring material, and remembering that synthetic oils are far more stable under extreme conditions(heat/pressure) YOu will hear horror stories about wiped out cams and such. But in a street motor, if you break it in properly and use a good quality oil you should have no problems. although a zink rich additive for Flat tappet motors is never a bad idea.
