If you own a 4.0L-powered Jeep, you've either had the exhaust manifold crack, or you're about to. Design flaws in the manifold almost guarantee failure at some point. One of our project Wranglers ...

But would this hold true for a modern engine like the 4.7L High Output V-8 in our WJ Grand Cherokee ... and a unique intake manifold to make 30 hp more than the standard 4.7L engine.