I have a 1998 Expedition with 5.4. I've had the manifold bolts break, I replaced the stock manifolds with Summit headers, and recently replaced them after they rusted out. My question is how do I keep the manifolds from leaking? I put on new gaskets from Summit along with the Permatex red, and used new manifolds from NAPA. I'm thinking of putting headers back on, only going with stainless steel, a cat back system, and chip. Any suggestions on the exhaust/headers would be appreciated.

 

i dont have any advice for ya but how long did it take before the summit headers rusted out. im thinking about putting them on only because i dont feel like putting out 850 for long tubes.

 

I didn't paint them before I put them ondue to time constraints. The headers didn't make it quite a year but I live in SW PA where salt and chemicals run rampant on the winter roads, and there was probably 30,000 miles run through them.

 

I thought that they came painted from summit? Yea i live right near the beach so i also have salt.

 

Also im planning on putting hi-flow cats on, do you happen to know what size the stock exhaust tubing is? I cant remember if it is 2.25 or 2.5

 

just use a quality gasket and make sure to torque the bolts the correct order.ive heard to retorque again after thay have heated up. otherwise they might work loose again. the stock pipe size is 2.5