[64speed]

On that map the closest one I won’t name I wouldn’t let him put a muffler on my lawn mower. The next closest is who I used. The rest are 30/45 mins away and I just don’t trust it that much yet. These magnaflow are a lot quieter than the black widows which may as well have been straight pipe. I have the Doug’s headers with the 3.5 inch outlets going into a Pypes 3 inch mandrel bent exhaust. I didn’t want crush bent pipe. No one around here mandrel bends. That’s Atlanta 160 miles from here

[HWYSTR455]

I just buy a kit, Pypes usually, hang it loosely, and drive up to have it welded. There's tons of custom shops around me, but very few have mandrel benders, if any.

One place I use will make minor adjustments before welding, and do a decent job for little money. Think they charged me $160 to do the GTO, but would have to check to be sure. It was something in that range though.


.

[grivera]

Originally Posted by Va68goat

I went with the Magnaflows on my GTO. I'm really happy with them and much better than the Flowmasters that I had before! This is a video that I found online. https://youtu.be/n61XIOVTmPk

What length mufflers on your GTO?

[64speed]

I was mistaken, I thought the 2nd closest one was where I got my exhaust. It’s not, the shop that did mine only does exhaust period. The rest of those are general service shops that might slap on a muffler.

[64speed]

I have sound deadener on the floor and plan on putting it on the doors. Where else should I put it?

[Scarebird]

Our cars do not come with them but one of the main areas for sound suppression is between the dash and firewall - hush panels they are called.

[HWYSTR455]

Originally Posted by 64speed

I have sound deadener on the floor and plan on putting it on the doors. Where else should I put it?

Ok, try to remember, the sticky tar mat is sound deadener, and does little as a thermal barrier. Will start by saying this.

Floor and doors are the biggie, but you should try to get as much as possible on the interior side of the firewall too. That's not always that easy, just try to do as much as possible.

Since you have a dash 'substructure', cut strips and stripe as much as you can of that. On the gauge insert, just try to make sure there's not a lot of loose wire and stuff. You can zip tie loose items/bundles, just don't pull the zip ties tight, leave them a little loose.

Doors, make sure all the lock & latch rods have the 'sock' on them, or use some other method to reduce rattle, like maybe pieces of vacuum tube or something. Those rods slide, so make sure they still move freely after. You can use short piece at strategic locations, you don't have to cover the whole rod(s).

The rear seat inner panels make a difference too, try to get some on those areas. You can cut strips and lay them on the inner wheel well too. I only go from the highest point forward to the floor, so you can't see it from the trunk. You can do the back part if you don't care about seeing it in the trunk.

I do the trunk floor, which for me gets covered with the trunk mat. Trunk floor helps reduce any drone from back there.

The rear package tray can be covered some, and helps. On the trunk divider, I used DynaLiner (thermal barrier) on the trunk facing side, it helps control the metal bracing resonance, and og course, thermal intrusion from the trunk.

I used DynaLiner on the doors and floor too. I used the thinner stuff on the door to ensure the door panels fit good, and thicker on the floor. Used a medium one on the firewall where I could, and on the package tray top.

I stripped off all the glued on matting from the carpet, trunk divider, and package tray so that would all fit better.

The sticky mat controls much of the resonating sound at 65-70% coverage, and the gain between that and 100% has little return. So don't kill yourself trying to get full coverage. The important part is to make sure it's as stuck as possible to the panels. (I do a quick wipe with acetone before applying).

I didn't do the roof in the A-bodies, since the sticky mat can droop from the roof getting hot. They make lightweight foil stuff, but I didn't bother. Your call there.

You can do the underside of the trunk lid if you want, but I didn't bother for the same reasons I didn't do the inside of the roof.

Cut out holes for the hardware, like seat & belt bolts and interior panel clips, it will save frustrations when you go to install stuff.

You can check people's build threads on how others have done it, or search YouTube for tips.

Aside from other mods I've done to cars, sound & thermal control is one of the most rewarding things I've ever done.

[64speed]

https://youtube.com/shorts/g9fsmYlukUU?feature=share

[geeteeohguy]

You'd be miles ahead as far as noise goes by losing the 3" exhaust and huge tips and moving to a sensible 2.5" system with Walker Turbo mufflers. Nice tone, no drone, can talk inside the car. I personally have no use for 3" exhaust on any street driven car.

[b-man]

3” all the way to some 3” to 2-1/2” reducers at the 2-1/2” mufflers and tailpipes would work nicely, once the exhaust gasses have reached the mufflers the gasses have cooled and contracted.

Since you already have 3” up to the mufflers already I’m assuming.

I sold my 3” system and went for 2-1/2” on my LS3 Tempest for less noise and better ground clearance since it’s lowered a couple inches. Even bought exhaust manifolds to replace the headers, just easier to work around and simpler as well as much better ground clearance.

[geeteeohguy]

Originally Posted by b-man

3” up to some reducers the 2-1/2” mufflers and tailpipes would work nicely, once the exhaust gasses have reached the mufflers the gasses have cooled and contracted.

Since you already have 3” up to the mufflers already I’m assuming.

I sold my 3” system and went for 2-1/2” on my LS3 Tempest for less noise and better ground clearance since it’s lowered a couple inches. Even bought exhaust manifolds to replace the headers, just easier to work around and simpler as well as much better ground clearance.

Years ago I watched a Fast and Loud episode where Rawlins bought a '67 Galaxie XL from the original owner. Car was absolutely cherry. Aaron proceeded to cut the floors and install an additional tunnel on each side of the driveshaft tunnel so they could fit 3" exhaust and bag the car. I turned off the TV and never watched that show again.

[64speed]

Now that I am driving it I’m pretty pleased with it. I can hear the radio now and will be fine I think when I put the interior in

[Gach]

Originally Posted by 64speed

Now that I am driving it I’m pretty pleased with it. I can hear the radio now and will be fine I think when I put the interior in

Glad to hear it…mean something turned out right finally.

[grivera]

Originally Posted by 64speed

Now that I am driving it I’m pretty pleased with it. I can hear the radio now and will be fine I think when I put the interior in

That’s all that matters!

[imposter]

i have a full 3" with x pipe and walker super turbos for years now and it's quiet

[64speed]

I’ve got almost everything worked out of any major concern. Except I can’t get one lifter to quiet ticking and I’m pretty sure it’s the one that backed off. I unlocked it and tightened it an 1/8 of a turn but I am afraid to go any further. It did get quieter though.

[Gach]

Originally Posted by 64speed

I’ve got almost everything worked out of any major concern. Except I can’t get one lifter to quiet ticking and I’m pretty sure it’s the one that backed off. I unlocked it and tightened it an 1/8 of a turn but I am afraid to go any further. It did get quieter though.

Some times a few maybe 1-2 need readjusting after its been run for a few miles or few hours of run time. Shouldn’t be big deal. Kind of like break in, and getting a littler wear on them.

[grivera]

Originally Posted by 64speed

I’ve got almost everything worked out of any major concern. Except I can’t get one lifter to quiet ticking and I’m pretty sure it’s the one that backed off. I unlocked it and tightened it an 1/8 of a turn but I am afraid to go any further. It did get quieter though.

Good you’re getting it sorted. How did you determine it was backed off?

[64speed]

Originally Posted by grivera

Good you’re getting it sorted. How did you determine it was backed off?

It was clacking like hell so I took off the valve cover and it was almost backed all the way off

[grivera]

Damn! If backed off that much will certainly need more than an 1/8 turn…Easily a 1/2 turn.