Since you mentioned the engine with a two barrel carb...  Your exhaust will sound totally different with the exact same system and a four barrel carb, with no other changes made.  I experienced this many years ago on a 383 stroker El Camino I had.

Exhaust sound is a strange phenomenon and I certainly have no idea how to tune one for a particular sound, nor do I know if the companies making the claims know what they are talking about.  Sometimes you just have to go with it and hope for the best.  I know from my own experience the flowmaster mufflers really do exactly what they say they will do.  I just wish they could do it in a smaller package

GPatrick wrote:

Is it possible/practical to cut a strip out of the casing of the Flowmaster and weld it back together to shorten it?  If the 50's are good but a little too long, can they be shortened enough to make them fit?  Seems like a lot to do on a new muffler but it would be worth it if they performed well and probably easier that designing a new one from scratch.

 That would change the chamber size and the sound would be different.  I hope the carchemistry resonators work better than you described!  I think the ones I am getting are totally different concept than the ones on your cobra.  I have my fingers crossed!

I have been swapping emails with Ken at CarChemistry.  It would be great if I could just install the Gibsons, test those, then install the CarChemistry resonators and compare with and without.  But logistics of installing the new mufflers dictates I install it all at once.  Whatever it sounds like, that is the way it is going to be...

I called Ken at CarChemestry and ordered 4 of the Baffle Builders. Will try them on Miss May first. As that is a bolt together 2.5 Stainless Magnaflow system I can slip a Baffle inbetween joins on different areas of each leg. Presuming I find the short in the 2+2's wiring.
The Vert won't do as I'm installing the Subframe connectors and Cross brace on it. After next weekend when we get back from Tampa Mustang Club Show. The current exhaust dosen't interface with the cross brack so all new will have to be fabricated. Soo Much to do Soo little time. Hehheh

Tubo
 

Tubo wrote:

During our time travling together at and to the Bash, Glen Buzek told me the drone is very common with the 351/5.0 firing order. A known Fox 5.0 issue. The two legs of a dual exhaust are like two tines of a tuning fork vibrating in synch, the 5.0 firing order is condusive to the Drone Harmonic at 2-2.5k RPM.
Take note of who has issues with "exhaust drone", and who has a 5.0 based engine. There is a distinct parallel.
Tubo

Is there any advantage to the 351/5.0 firing order vs. the older 289/302 FO? I will be putting a roller 5.0 into the 66 pretty soon (90k donor motor w/T-5 that'll keep me rolling while I save up for a Dart based stroker). I probably won't bother with the 5.0 donor since it's all about a budget replacement for the high-mile 302 and will get me into the T-5 from the current C4, but what If one had a roller cam ground that would allow one to use the older FO? I'm planning on the stroker to be internally balanced if that makes any difference. Hmm...

Last edited by McStang (10/20/2013 10:43 PM)

McStang wrote:

Tubo wrote:

During our time travling together at and to the Bash, Glen Buzek told me the drone is very common with the 351/5.0 firing order. A known Fox 5.0 issue. The two legs of a dual exhaust are like two tines of a tuning fork vibrating in synch, the 5.0 firing order is condusive to the Drone Harmonic at 2-2.5k RPM.
Take note of who has issues with "exhaust drone", and who has a 5.0 based engine. There is a distinct parallel.
Tubo

Is there any advantage to the 351/5.0 firing order vs. the older 289/302 FO? I will be putting a roller 5.0 into the 66 pretty soon (90k donor motor w/T-5 that'll keep me rolling while I save up for a Dart based stroker). I probably won't bother with the 5.0 donor since it's all about a budget replacement for the high-mile 302 and will get me into the T-5 from the current C4, but what If one had a roller cam ground that would allow one to use the older FO? I'm planning on the stroker to be internally balanced if that makes any difference. Hmm...

That could be done.  The standard 5.0 from the TC, Crown Vic, and Grand Mq.  had the old fireing order.  The only issue is  if  you are running the mass air EFI and then it will just create a slight idling issue.  What happens is  that while you can change the firing order to match the cam, you can't change the Injector firing order cause it confuses the PCM.  What happens is that at idle you have a few cylenders that have a small puddling issue in the port.

But (TS&T)...if you are running a pot, no problem.

BB

MS, sounds (no pun intended) like you're getting close.   Can you record each muffler (Gibson vs Carchemistry) with the different variables for each, ie, driving, accelerating, idling, in the car, out of the car,  and post them?

MustangSteve wrote:

Bullet, why can't you just rewire the injectors so the correct cylinder is getting gas at the right time?  Seems simple enough to do...  Didn't Hakan do that on his?

Because the O2 sensors will give the computer feedback from the wrong cylinders.  Then the computer will go nuts trying  to get things right with the wrong info coming back.

Just change the dizzy firing order and it'll work fine.  You'll just loose a bit of atomization at idle but off idle things are happening so fast that the  engine won't notice.

Your's probably won't care, Steve, since it's a TB setup and not sequential.
BB

Last edited by Bullet Bob (10/22/2013 11:36 AM)

MustangSteve wrote:

Gibson mufflers showed up today.  They are center IN, offset OUT, exactly opposite of what I need.  Now it will cost me $44 to send them back and no telling how much more to get them to send the correct ones.  And I even called to verify where the inlet and outlet were before I ordered !
I may just join 6sally6 and run a straight pipe...

.......huh?!
 

I think the issue is with the high HP 427 pushing alot of air.  I had a pair of the Dynomax mega flows shipped to me but I chickened out and sent them back before installing them, rather opting for the Gibsons.  We'll see how it turns out if I can ever just get the right mufflers in hand!

I guarantee that whatever goes on there this time is what is going to stay! I am tired of messing with it.

What are people's thoughts about a fastback producing more noticable drone than the coupes and verts? Granted, my coupe and my brother's vert both had only about 250 hp and 2-1/4" pipes, but they sure seemed quieter to me...of course, I was in my 20's then 

Steve, Please post a recording of your final outcome would love to hear it.