my question is - will I benefit with torque/HP gains by adding full length headers, high flow cats, but keeping my factory muffler? I need to replace the factory manifolds because they're rusted out and starting to leak, so I figured I would do headers etc but I don't want a loud muffler added... will I still benefit in performance?
My car has 62000 miles.
My car has an automatic transmission.
Warped manifolds are a well known problem on the 5.4L engine. My personal F150 has a noticeable exhaust leak from the manifolds on cold start, but goes away once the engine warms up and the manifolds expand. As for adding performance headers and exhaust, there will be a small gain in power due to reduced back pressure. However, it’s not likely to be a noticeable gain you’ll feel while driving. I recommend having a professional replace the exhaust manifolds with OEM equivalent parts. YourMechanic is an excellent option since we come to your home or office
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