whiskeybent

If your running hi-flow cats, maybe you have damaged a converter. Please let us know what you find out. Thanks

Ok with that sound lets address the "puffing" air sound, you may have an exhaust leak, verify this by looking at all connections to see if there is any "black soot" around the connection points, this means you have a leak. Another possibility is a damaged muffler, if this was the case, you will notice really strange sounds at all RPM levels. Is your vehicle supercharged by any chance? If the sound is getting worse, maybe an exhaust component is rubbing the frame of body? Are you running hi-flow cats?

Thanks for the info Whiskey Bent, ok couple of things. The OHC design of these Ford engines creates this drone in the 1400-1800 RPM level, this is normal with any exhaust system and is prevalent on the Mustang, GT-500 and the F-150. We sponsor a number a number of forums and see many threads based on the "Ford" drone, this is why the stock system uses a resonator and huge muffler. Upon a cold startup these motors will make a number of strange sounds, we typically do a few Raptors per month and always are amazed at the strange sounds in the A.M.

What modifications do you currently have in combination with our headers and exhaust, be specific to intake and tune. Also, what RPM is the sound at, please be specific. Lets go from there maybe we can offer some advice. Have you sent us any pictures of the truck by any chance, if not we would love to see some.
Thanks,
Paul G.