Headers? Yes? No?

[donl]

Gearing up to "restore" my '03 4.6L Expy with 150K miles. Very well maintained, motor and trans in good condition. Plan is to restore interior and exterior to "showroom" condition. Vehicle is already lowered with Eibach/Bilsteins and 20" wheels/tires and upgraded radio with hands free, navigation, etc.

Mechanical plan includes 4.11 gears, under drive pulley kit, 5 Star tuning, CAI and shorty headers. Debating on headers as it has been a while since owning a vehicle with headers; don't want to increase cabin noise. With the other modifications, I am not sure that whatever gain I might see from a set of shorty headers is worth the trade off for an increase in cabin noise but I don't know if there will be an increase in cabin noise.

What say you that are running headers regarding increased cabin noise?

 

[1955moose]

The problem with most headers is not much increased noise, but constantly having to deal with gasket fit/sealing, and stud/nut tightness. In the old days getting at oil filter and spark plugs was a problem. The noise and sometimes a droning sound comes from the exaust mufflers themselves. Headers definitely help middle to top end performance when adjustment of fuel matches increased breathing, but keep in mind you'll also lose the bottom end a bit. When you deal with any mods, theirs always a trade-off. That's why most hotrodders do bigger pistons, higher compression, etc to make up for what they lose. Then you have a win win situation. Power from idle to 7 grand.

Sent from my N9131 using Tapatalk

 

[donl]

Thanks for the reply. So, are you saying there is increased cabin noise or not? If so, how much of an increase? I did replace the Magnaflow muffler that came with the catback system with a Walker piece because of that drone you speak of. The Walker is near droneless; just a tweak over stock and would not be noticed by anyone but me.

I am familiar with the impact of headers, cams, more displacement, head porting, etc., etc.. Ran a B/MP car back in the late 80's up and down the Gulf Coast and build performance motors for Harley Davidsons, so I also understand the trade-off you speak of as well as how to minimize it. The gear change from 3.73's to 4.11's will compensate for any loss of bottom end from the other modifications which I expect to be marginal.

Not building a hot rod, just want to add a measurable bump to TQ/HP as part of the restoration. Thanks again for the reply.

 

[HawkX66]

With the right system, the 4.6L sounds great. I helped my son put headers on his GT when we rebuilt the engine. It depends on you whether the juice is worth the squeeze. With new fastener options like Stage8 header bolts and better sealing gaskets, the leaks of yesterday can be eliminated.
My guess is that, unlike with the GT, fitment won't be an issue with the size of the engine bay.





See the header bolts in this pic. No leaks after about 5k miles.

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[donl]

With the right system, the 4.6L sounds great. I helped my son put headers on his GT when we rebuilt the engine. It depends on you whether the juice is worth the squeeze. With new fastener options like Stage8 header bolts and better sealing gaskets, the leaks of yesterday can be eliminated. My guess is that, unlike with the GT, fitment won't be an issue with the size of the engine bay.

Thanks for the heads up. Please clue me in on the source for the Stage 8 header bolts and the better sealing gaskets. Fitment is not really an "issue" but the R/R is a true PITA. Some remove the inner fender to make it much easier. I will not do this install; have a local independent that does this stuff daily and he will do the work.

No comment on increased cabin noise?

 

[HawkX66]

Thanks for the heads up. Please clue me in on the source for the Stage 8 header bolts and the better sealing gaskets. Fitment is not really an "issue" but the R/R is a true PITA. Some remove the inner fender to make it much easier. I will not do this install; have a local independent that does this stuff daily and he will do the work.

No comment on increased cabin noise?

I would go with long tube headers for starters. That's where you're going to get the benefits. A quick google search for Stage 8 will give you a million different vendors. Summit Racing being one of them. Amazon? etc. Percy's sells aluminum gaskets that work well. There are a million different options. These are just a few that have worked in the past for me.
Cabin noise. That I can't really comment on because I haven't driven in Ex with headers. Generally speaking you're going to get some, but if it's a good install, it should be coming out the tail pipes and not from any echo in the engine bay.
FWIW, I'm a big block Chevy guy. I have a 69 Camaro big block that I built. With that said, I still really am impressed and love the sound of my sons Mustang. Very "throaty." Stainless headers, off road H pipe and flow master muffler/exhaust.

 

[donl]

I would go with long tube headers for starters. That's where you're going to get the benefits. A quick google search for Stage 8 will give you a million different vendors. Summit Racing being one of them. Amazon? etc. Percy's sells aluminum gaskets that work well. There are a million different options. These are just a few that have worked in the past for me.
Cabin noise. That I can't really comment on because I haven't driven in Ex with headers. Generally speaking you're going to get some, but if it's a good install, it should be coming out the tail pipes and not from any echo in the engine bay.
FWIW, I'm a big block Chevy guy. I have a 69 Camaro big block that I built. With that said, I still really am impressed and love the sound of my sons Mustang. Very "throaty." Stainless headers, off road H pipe and flow master muffler/exhaust.

Thanks, Summit Racing is a source I have used in the past. I do understand and agree, to some extent, your comment on long tube headers but that isn't going to happen. Recently replaced everything from the exhaust manifold back, i.e., cats and OEM exhaust was replaced with Magnaflow cat back system aside from the fact that this vehicle will see 100% intown driving except an occasional 150 mile interstate trip to visit family so I really don't need the additional top end benefit that come with long tube headers.

The B/MP car I referenced in #3 was a '56 Chevy Bel Aire powered by a 350 Chevy stroked to 372CI with a tunnel ram manifold for two Holley's, etc., etc.. It would barely pull itself out of it's own smoke below 5000 rpms. I converted to Fords, no particular reason, when I replace my sedans with SUVs.

Thanks again for the information.

 

[HawkX66]

Thanks, Summit Racing is a source I have used in the past. I do understand and agree, to some extent, your comment on long tube headers but that isn't going to happen. Recently replaced everything from the exhaust manifold back, i.e., cats and OEM exhaust was replaced with Magnaflow cat back system aside from the fact that this vehicle will see 100% intown driving except an occasional 150 mile interstate trip to visit family so I really don't need the additional top end benefit that come with long tube headers.

The B/MP car I referenced in #3 was a '56 Chevy Bel Aire powered by a 350 Chevy stroked to 372CI with a tunnel ram manifold for two Holley's, etc., etc.. It would barely pull itself out of it's own smoke below 5000 rpms. I converted to Fords, no particular reason, when I replace my sedans with SUVs.

Thanks again for the information.

Gotcha. Don't know how I missed the info about your B/MP car! Sounds awesome. I think you'll appreciate this pic. It's of my Dad back in the late 60s/70s racing at New England Dragway. 62 Nova w/ 426 Hemi, Hilborn fuel injection etc. It actually had a big Pontiac motor in it in this pic. I grew knowing it with stacks sticking up out of the hood. That was my playground...

 

[donl]

Cool picture. Those days are gone though; not really a "hobbyist" sport now.

 

[HawkX66]

Cool picture. Those days are gone though; not really a "hobbyist" sport now.

Maybe not where you are, but there are plenty of guys still ripping it up on "test and tune" nights. You just can't compete without sponsors or deep pockets though.