Need to quiet down our 484 FE...

[frnkeore]

There is a very interesting thread going on at ST, regarding exhaust noise:

https://www.speed-talk.com/forum/viewtopic.php?t=68357

It is something that should help in a street engine, too. Might be worth a try.

[CV355]

None of this makes sense to me. I've had slip joint headers that showed the black marks from exhaust exiting between the joints....never smelled anything, or heard leaks. IF there was anything to hear, it was only at full throttle, where I couldn't hear it anyway over the carb and/or exhaust note. I most definitely never smelled like exhaust from driving, or smelled it at all for that matter.

Not counting a really REALLY bad leak at the head or collector, the only way I've smelled exhaust in the car (also a Mach 1), was when my exhaust terminated at the rear axle, OR when the exhaust didn't protrude past the rear valance, where it gets trapped under the car and makes its way back into the trunk, or back to the side windows. That is definitely an issue. I just don't believe a small joint leak could produce enough fumes to smell inside, let alone cover the driver. Almost 40 years of driving my Mach, with different engines, different headers, different mufflers...or no exhaust at all, that is my experience.

Sound can be a funny thing. Certain frequencies can trigger really annoying reactions, especially as a person ages and their hearing changes. It may be the case here, where a certain frequency from those particular thin wall headers is just not playing well with your hearing. But in fairness, I've never ran REF headers, so can't say whether or not they are worse, or just different, than others.

I'm putting the car up on the lift this weekend, checking every connection and re-torquing all of the exhaust flange bolts just to be safe.  I see no smoke, there are no oil leaks anywhere.  I do have electric cutouts but they are sealed well and it's all welded from the collector flange back to the mufflers.

Here's an example of the noise level in front of the car vs behind at the tailpipes. 
https://streamable.com/rrjdob

[Gregwill16]

Sounds great to me!

[Jb427]

sounds good to me too
The cut outs I would think that is your fume problem

[Tunnelwedge]

Awesome car.
Sounds like exhaust under the hood.
Open the hood and do a sound check.

[machoneman]

None of this makes sense to me. I've had slip joint headers that showed the black marks from exhaust exiting between the joints....never smelled anything, or heard leaks. IF there was anything to hear, it was only at full throttle, where I couldn't hear it anyway over the carb and/or exhaust note. I most definitely never smelled like exhaust from driving, or smelled it at all for that matter.

I agree as it doesn't make any sense to me either. Something under the car must be missing, like a shifter boot, or holes in the floor pan are allowing the smell in. Maybe firewall gaps yet airflow should not allow it. Maybe test the cowl by using some blue painter's tape to seal it off 100% as see if that makes any difference.

[Tunnelwedge]

My sound check.
Both my FE's running. 428 with Hookers and 482 with Hookers.
If either one of mine was making that much noise under the hood I be changing something.
My Bro even said exhaust. The 482 pop just once and then 15 mins later shut down on the pass.
Pertronix let me down.

https://www.youtube.com/shorts/Rb1R_2wkHvk

[CV355]

My sound check.
Both my FE's running. 428 with Hookers and 482 with Hookers.
If either one of mine was making that much noise under the hood I be changing something.
My Bro even said exhaust. The 482 pop just once and then 15 mins later shut down on the pass.
Pertronix let me down.

https://www.youtube.com/shorts/Rb1R_2wkHvk

Yours sounds excellent.  It looks like everyone is in agreement that the sound I'm experiencing is not typical header ping and there's a leak somewhere.  I'll re-torque everything and try again.  I'd love to get this resolved without having to change out exhaust components.

[Jb427]

Just my opinion but I don't think a header leak is your problem a header leak sounds more like a tick
the ring problem could be from your headers i could see that if they are made out of really thin or even stainless can can make it sound tinny.

I would delete the cut-outs first or make them removeable every one I have ever know who has used them has never had good luck and have problems with them not sealing and leaking over time
after they have been deleted test and if it changes anything it may fix sound and smell problem it one hit they are the biggest potential leak area.

Just my opinion but that is what I would try first I hope you get it sorted.   

[TurboChris]

I would delete the cut-outs first or make them removeable every one I have ever know who has used them has never had good luck and have problems with them not sealing and leaking over time

Agreed. My Fairlane had Granatelli electric cut outs on it from the previous owner. Took me a minute but I eventually noticed that they always seemed to be leaking. I'd close them, sounded good. But a few mins later.....leaking loud enough to bother me. I eventually yanked em and installed electronic mufflers. Pretty quiet when closed and noticeably louder when open. Way better than the cut outs and Flowmaster 40's that were on there.

https://xforceusa.com/varex-mufflers/?gad_source=1&gclid=Cj0KCQjwlN6wBhCcARIsAKZvD5hUbHIDhHtvsJbvqyARGGslKLEBT9vGqLAlwCoENUWC4IIwMEMkvUIaAkniEALw_wcB

[CV355]

I went through and made sure every header bolt was torqued, nothing had loosened and there was no evidence of a leak at the heads.  I think the issue is at the collectors, and it directs the noise towards the front of the car.  I crawled under while the engine was running and there is no leak anywhere near the cutouts.  There is no room for a clamp, short of me removing the collectors, slotting each primary tube and welding on draw tabs.  I may try the permatex method and hope it doesn't blow out.

I did find the main culprit for the exhaust stench.  The hood scoop blinker harness had pulled forward (CVF hinges open higher, so I needed a larger strain relief) and the grommets were no longer sealed up by the cowl.  That was an easy fix.  Every other area was sealed properly on the firewall and under the car.

Overall it is running great and I have worked out every other major issue.  Drives are getting more enjoyable and less nerve-wracking. 

[Jb427]

Glad to hear your getting it sorted out