Theres a few things in that write up I disagree with. For the most part he's generalizing and it sounds plausible,.. but when you think about it,.. it makes absolutely no sense.

About 20 years ago I read an article written by a GM engineer. He was on the team that designed the TPI intakes. He specifically stated that in order for the engine to run at optimum efficiency, that some back pressure is needed. The induction system was design for it.

The guy in the article is talking about exhaust gas velocity. Once the exhaust passes the manifolds why the hell would it NEED velocity anymore? Using a 4" exhaust would kill power,.. yet open headers will not? Come on. I can see velocity being needed in the induction. Yes.,. I agree 100%. And with a forced induction engine,.. I can understand where velocity is crucial. But I dont see where it plays that big of a deal with an NA engine,.. well at least once its passed the manifolds as long as the exhaust is not restricting anything I dont see where it would lose anything by virtue of lost velocity at the mufflers. It goes against so many other articles written by experienced well known engine builders.

Smokey Yunic wrote a book book on the subject a while back. I dont have it anymore. I'm trying to find it online. You guys cant argue with old Smokey,.. he is a legend.

Hurst