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My frankenexhaust with GT500 mufflers and GT350 valence

sonicc

Mr. Bond
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Figured I'll share this here in case anyone is wondering how these mufflers sound or fit...

First just wanted to give big thanks to another member here [MENTION=16477]El_Centenario[/MENTION] . He was the one that has installed these mufflers before me and then answered a bunch of questions I had before starting. I was originally going to follow his footsteps and go with the Roush valence, but a GT350 valence came up on Craigslist for a good price and I just had to do it. I also found the GT500 for very cheap in one of the local Mustang classifieds group.

Now, if you're wondering about fitment...using the Roush valence would make this job 10x easier because you don't have to modify the muffler tips. Overall it took me 3 days of cutting, welding, and grinding to get everything to line up. Obviously, I've never done anything like this before so I'd say there's some learning curve to exhaust fabrication lol. I'm sure someone more experienced with proper equipment could knock this out in less than a day. I was looking into having a shop do this but the answers ranged from "it won't fit" to "it will be cheaper to just buy an exhaust made for your car". Had one Mustang performance shop willing to do the work at a reasonable price, but they kept d!cking me around too much and after being rescheduled for too many times I gave up. So what did I do? Went to Harbor Freight, picked up a flux core welder (yep...), and practiced for couple days before going at it. I'm one of those people who believe that just because a weld looks pretty doesn't make it strong...sooooooo....yeah :D

Anyway, before posting some pictures of the parts and stuff I figured I'll post a first start up with mufflers just loosely installed. Just a note I do also have an X-pipe that was previously installed.



As you can tell it sounds fairly aggressive but the video doesn't do it justice. I buttoned up everything and took it for a drive yesterday, the sound is intoxicating. Almost 0 drone on highway and cruising in 6th at 70 mph it's barely louder over stock mufflers.

Now onto the pictures...

What I started with:
yjtbjct.jpg


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Bunch of 2.5" aluminized tubing from eBay
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Great mock up skills with blue tape!
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My original plan when I got the piping was to just build out the piping from x-pipe to the mufflers, but ultimately decided not to do that. The stock exhaust piping is the same diameter and really not restrictive once you cut off the stock mufflers at the weld point. Second reason I didn't want to go building the rest of it is because I couldn't get the Harbor Freight exhaust pipe expander to expand the new piping enough so I can slip one pipe onto another then weld them (slip joint). I'd have to go with "butt-joint" which I did not feel like it would be strong enough to last over time with flux core welds. If I had a TIG welder and some practice I would have probably done it as it gives better control and more precision. It does not take a whole lot to burn through 16gauge pipe with flux core even on low settings :(

Cutting off the original tips from GT500 mufflers and "fabricating" new ones. The original tips were not spaced far enough to fit into GT350 fake tips correctly. What I did here was take some offset pipe (s-shaped) and then cut it at 15 degree with mitter saw. There are probably better ways of doing this, I just wasn't able to figure an alternative given the parts and equipment I had. Someone with a TIG welder could probably do pie-cuts and make a prettier offset, but it is what it is :D
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Blue tape ftw!
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The "offset" tip welded on. That dark spot is not a hole btw, just some flux core stuff that didn't get cleaned up. Had to just tack-weld around the tip twice as it would easily burn through between two edges or warp:
i7MDF4h.jpg


Second tip welded and muffler hanger moved up
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Original inlet pipe had to be cut off, wouldn't work with S550:
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Welding the new inlet pipe went a lot easier and smoother because I was able to push it into the muffler and do a slip joint, then welded once on low setting and then on higher setting (I think I'm also getting better at welding)
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Over the weekend I'll have to smooth out the tips make the edges more flat, hit the tips and mufflers with some flame resistant paint to protect from rust, and then install them again. Hopefully I can get a better video with my DSLR and get some in-cabin sound as well.

Anyway, sorry for the long post and thanks for reading.
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sonicc

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Thanks, man. It definitely took some work but it was something I've been wanting to do.
 

mikes2017gt

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I think you're doing a great job, man! It takes real thought to figure out which parts to buy and how you're going to put them together. Sounds and looks awesome!
 

Red Turtle

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I loved the sound of my Boss 302 with GT500 quads and Borla resonator delete OTA pipes. Your description of intoxicating is very accurate. Keep up the quest and good work.
 

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sonicc

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Didn’t think that quad tip GT500 muffler would work with the shelby valance. Pretty big muffler.
It fits, but it's very tight fit. While the GT500 mufflers are few inches longer than stock 5.0 mufflers, they're the same height. I will try to get some better pictures once I have the car in the air, hard to take good pictures of the mufflers with car on jackstands.
 
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Updated video with cold start up, idling, and some revs:




If anyone is wondering about the cost of all the parts/materials:
GT500 Mufflers: $150 (used)
GT350 Valence: $150 (used)
eBay piping and clamps: ~$130
 

El_Centenario

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Looks great! I would have done the gt350 valance too but they were not easily available when I did my exhaust. I'm glad I was able to help out!
 

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BmacIL

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[MENTION=6944]zackmd1[/MENTION] I'd do this except not cut the tips off since you've already got a bumper valence that will fit them. Pair with an X-pipe resonator delete and enjoy.
 
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[MENTION=6944]zackmd1[/MENTION] I'd do this except not cut the tips off since you've already got a bumper valence that will fit them. Pair with an X-pipe resonator delete and enjoy.
I toyed around with that idea but it wouldn't work. Tips are too close and look fugly with this valence
 

BmacIL

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I toyed around with that idea but it wouldn't work. Tips are too close and look fugly with this valence
Even with the 2018 bumper?
 

Rodan

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Looks (and sounds) great! I'd love to see a driveaway video.

I've been researching what mufflers to use as I've been planning to convert our '17 GT to an '18 bumper cover/valance. I just love the quad tips, and I guess I'm getting old because most of the aftermarket stuff is too loud. :p

Not to mention the price of exhaust systems is crazy these days.
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