Mopar head question-Thanks

This was never about Me and Zach using them (see my original question) but why the W9's are not a everyday use kind of thing,Like I said I've had my head buried in the building small block stroker book and the author talks a lot about W9's and I was wandering why you don't see more guy's using them,lot's of good info here.Thanks Steve

Edelbrock syndrome ;)