Ford F-250 Engine Vacuum Leak

I Have A Loud Roaring Sound From Engine And I Cant Pinpoint It, Took To Ford Dealer And He Said Vacuum Leak Somewhere But Not To Worry,but...

A 3/8 Black Hose Can't See Where Or What It Attached To. It Is Under The Intake Manifold On Passengers Side

Firing On All 8.is Rough At Idle As Though A Vacuum Leak I Unplgged Large Unused Vacuum Port Up On Manifold And Truck Runs Perfect?even At...

The Ford Came With A 352 Engine But Blew It Up So We Put A 390 In It And It Blew It Up Too, We Thought It Might Have A Vacuum Leak But Ruled...