Jeep Engines - Oljeep

360 AMC V-8 (INDUCTION SYSTEM) 419~Intake and Exhaust Manifold Attaching PackagePackage of factory original nuts and bolts to attach intakemanifold and exhaust manifolds. Includes 24 bolts, 24washers, 4 studs and 6 plugs. For 360 AMC V-8 engineonly.P452968 1Vacuum LeaksIntake and exhaust manifold attachingpackage.All engines need an intake manifold of some kind, andusually they are made of cast iron or aluminum. Althoughcommon on standard production vehicles, using a cast ironintake manifold in racing is fairly rare. Aluminummanifolds are typically used in both drag and oval trackracing. Despite these different applications, cast iron andaluminum intake manifolds do share one commonproblem - vacuum leaks.Vacuum leaks are perhaps the most common type of intakemanifold problem. Once solved, vacuum leaks aren’t likelyto return, but when you first install that new intakemanifold, they can be very troublesome.The most common locations for vacuum leaks are theintake flanges next to the heads. The second most commonare the various ‘‘taps’’ that are screwed into the intake (oneor more). On a race manifold these taps may not exist. Inthis case, the holes are typically plugged. However, a leakmay exist around the plug.Typically, an aluminum intake manifold is an aftermarketpiece. This means it is not a production intake manifold.There are a couple exceptions to this, but we’ll assume thatyou’re using an aftermarket intake. These manifoldsgenerally have a “dual” mounting pad for the 4-Bbl.carburetor. This allows all the popular carburetors to bebolted to the same intake manifold. This is easily observedby looking at the carburetor mounting flange with thecarburetor removed and counting the holes machined andtapped. A dual mounting pad will have eight holes.The trick here is related to the way single plane intakemanifolds are made-one of the carburetor mounting holesmay be machined into (or “leak” into) the top of the “runner”or “plenum.” This is possible even in production manifolds.However, the production manifold typically only has fourholes and any potential vacuum leak would be plugged oncethe carburetor is installed. This can be further ensured byusing sealer on the carburetor attaching bolt threads.With the eight hole flange and the carburetor installednormally, four holes are left unfilled. To ensure againstvacuum leaks, you should plug the threaded bolt holes thatare not going to be used. Why mention anything thissimple? It is easy to overlook, and once you’ve assembledthe carburetor on to the manifold, it can be almostimpossible to find and can cause you a great deal of trouble... T -17