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I think I castrated my Shelby….and I’m not happy about it

mavisky

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Headers don't give enough return for the money and why would you mess with a Shelby?
Believe it or not, but the car has deficiencies depending on what your intended usage is. However there are exactly 0 cars I can think of that sound good while cruising and at WOT without some restriction in the exhaust in terms of muffling, resonators, or cats.
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K Myers

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It’s a 2017 Shelby GT350, beautiful car but just like every other guy on this forum, why keep it stock? I went ahead and picked up the infamous JLT intake and paired it up with a set of Stainless Works LTH’s, and also put in an MBRP X-pipe, and I have to say I’m not on board with it yet. First off, the enclosure for the JLT was too high so it propped my hood up. Had to shave off about 1/4” to get the hood back down and fitting right. I tuned it and didn’t feel any appreciable difference in power, but hey, who can honestly feel the advertised 8-12hp bump anyway.
But then the exhaust….where to start with the exhaust. With the stock exhaust and MBRP, whenever I would downshift or coast in gear, it sounded like demons shrouded in a thunderstorm were fast approaching. And at wot, it had a deep growl that just meant business.
Then I added the the Stainless Works LTH. The first cold start was alarming to say the least. It was ear splitting loud. Driving it normal on the interstate wasn’t bad though. But I did lose the melodious thunder that I was accustomed to. And then there was the wot pull. Oh my….I let off at 7k because I think I heard some dogs howling in pain a couple of counties over. This thing screams like sheep at a slaughter house. It’s no longer that growl that I look forward to hearing. It’s more like the local teenagers meeting at the sonic with their gutted cherry bomb mufflers.
Now as far as performance? I had the car dynoed stock, and it put down 477 to the wheels. I was told that was unusually high. After a custom dyno tune with all of the new goodies….. 485. Yeah, that’s 8hp. Two different dynos, so I get there are discrepancies, but just 8hp after almost $3k in parts and a custom tune? I’m just not seeing the juice being worth the squeeze! The real test will be in May when we take her to a track day to see if we have any time improvements with that 8hp.
Sad to say but you need a custom tune not a cookie cutter tune I had a cookie cuaternario from Bamma it was a step up from stock I add headers w/o cats and a Rob Shoemaker tune what a diffrence
 

young at heart

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But you’re fighting the engineering that make it such a great twisty, road course car (trans, gearing, suspension, etc).
I realize that what I’m about to say will be the digital equivalent of finding a turd in the punch bowl, and I apologize in advance. But reading so many failed mod posts it increasingly occurs to me that one’s best bet by far may be to just buy the basic car that best suits you to start with and don’t try to outsmart the engineers that designed it. Maybe only the failed science experiments get posted, I don’t know. Anyway, it’s just a casual observation and I’m not trying to state a fact. Plus, I’m flaky and wishy-washy as heck and next week I may have a GMC 6~71 poking through the hood of one of my cars. There’s that.

One more thing, kinda related. Given the unbelievably beautiful sound that comes from a stock GT or Mach 1 running in track mode, I can only imagine how good a GT350 must sound live and in person. The videos alone border on qualifying as pure porn. I personally couldn’t imagine trying to improve it but clearly that’s just me.
 

MAGS1

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I realize that what I’m about to say will be the digital equivalent of finding a turd in the punch bowl, and I apologize in advance. But reading so many failed mod posts it increasingly occurs to me that one’s best bet by far may be to just buy the basic car that best suits you to start with and don’t try to outsmart the engineers that designed it. Maybe only the failed science experiments get posted, I don’t know. Anyway, it’s just a casual observation and I’m not trying to state a fact. Plus, I’m flaky and wishy-washy as heck and next week I may have a GMC 6~71 poking through the hood of one of my cars. There’s that.

One more thing, kinda related. Given the unbelievably beautiful sound that comes from a stock GT or Mach 1 running in track mode, I can only imagine how good a GT350 must sound live and in person. The videos alone border on qualifying as pure porn. I personally couldn’t imagine trying to improve it but clearly that’s just me.
I think there’s good examples of successfully modified 350’s in here too (and outside of this forum as well), I know there’s at least a few that have Whippled or turboed their 350’s with no or few issues.

At least in my opinion, it’s not built to be a straight line car so you’d have to throw extra $$ at it to get it there. Especially the R, it’s made for road courses, twisties, etc. That’s where it really excels. Not that you can’t get it there because it’s absolutely possible, I just don’t think that’s the reason most people buy the 350. They buy it for where it’s really good right out of the box.

As for the sound, for me, it’s one of if not the best sounding V8 out there. Resonator delete on a non-R (the R’s come with an X pipe from factory) is the only thing I’d touch as far as the exhaust goes. It just sounds so good as is.
 

galaxy

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Resonator delete on a non-R (the R’s come with an X pipe from factory) is the only thing I’d touch as far as the exhaust goes. It just sounds so good as is.
They all come with the same X pipe from factory. Only the actual resonator is different.
 

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It’s a 2017 Shelby GT350, beautiful car but just like every other guy on this forum, why keep it stock? I went ahead and picked up the infamous JLT intake and paired it up with a set of Stainless Works LTH’s, and also put in an MBRP X-pipe, and I have to say I’m not on board with it yet. First off, the enclosure for the JLT was too high so it propped my hood up. Had to shave off about 1/4” to get the hood back down and fitting right. I tuned it and didn’t feel any appreciable difference in power, but hey, who can honestly feel the advertised 8-12hp bump anyway.
But then the exhaust….where to start with the exhaust. With the stock exhaust and MBRP, whenever I would downshift or coast in gear, it sounded like demons shrouded in a thunderstorm were fast approaching. And at wot, it had a deep growl that just meant business.
Then I added the the Stainless Works LTH. The first cold start was alarming to say the least. It was ear splitting loud. Driving it normal on the interstate wasn’t bad though. But I did lose the melodious thunder that I was accustomed to. And then there was the wot pull. Oh my….I let off at 7k because I think I heard some dogs howling in pain a couple of counties over. This thing screams like sheep at a slaughter house. It’s no longer that growl that I look forward to hearing. It’s more like the local teenagers meeting at the sonic with their gutted cherry bomb mufflers.
Now as far as performance? I had the car dynoed stock, and it put down 477 to the wheels. I was told that was unusually high. After a custom dyno tune with all of the new goodies….. 485. Yeah, that’s 8hp. Two different dynos, so I get there are discrepancies, but just 8hp after almost $3k in parts and a custom tune? I’m just not seeing the juice being worth the squeeze! The real test will be in May when we take her to a track day to see if we have any time improvements with that 8hp.
I had a Roush that I did the same with. The shop called to say they were dropping the car off to me. I waited outside when I knew they would be near by. As soon as they pulled into my development, exactly 1 mile from my house, I heard it.
Car came home, I hated it. Gave it the night without starting it. Went out the next morning to go for a ride. I ended up going directly to the shop and having them removed! Best mod I never did.
Since then I have owned another 8 Mustangs, including a GT350 and a few 500’s. I have left the exhaust stock on every single one.
 

Nfs1000f

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Why modify the exhaust system for the best sounding V8 in the world????????
Let me confirm your assertion.
 

MAGS1

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Let me confirm your assertion.
Love it. One of the guys in my neighborhood that has one had his out yesterday because the weather has been so nice. Best sounding V8 in my book. While some videos can do the sound justice, it’s just so fantastic to hear in person.
 

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young at heart

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Never gets old.
As the owner of a “regular” GT with AVE and two Mach 1s, all three of which run exclusively in track mode, let me paraphrase one of my all-time heroes, Mr. Fred G. Sanford: beautiful sound may be skin deep but bad ass goes right to the bone!

Now I’m not saying one is better than the other, that’s a personal call and for me it changes from day to day. And I do love my Coyotes. But I am saying that right there is truly some bad assery and if exhaust sound were art it’d be hanging in the Louvre.
 

rolfe.oliver

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I think there’s good examples of successfully modified 350’s in here too (and outside of this forum as well), I know there’s at least a few that have Whippled or turboed their 350’s with no or few issues.

At least in my opinion, it’s not built to be a straight line car so you’d have to throw extra $$ at it to get it there. Especially the R, it’s made for road courses, twisties, etc. That’s where it really excels. Not that you can’t get it there because it’s absolutely possible, I just don’t think that’s the reason most people buy the 350. They buy it for where it’s really good right out of the box.

As for the sound, for me, it’s one of if not the best sounding V8 out there. Resonator delete on a non-R (the R’s come with an X pipe from factory) is the only thing I’d touch as far as the exhaust goes. It just sounds so good as is.
I did not get my 350 for the drag strip. Drag racing a GT350 is dumb: the clutch will literally explode, the TR3160 does not like gorilla shifting, there is no low end torque, and the suspension is tuned for the compete opposite of that. Sure, you can make a GT350 a fast 1/4 mile car. But that is not my goal.

I am modifying Mine to be a quick street car. PD blower coming to fix the torque and then I retain all the creature comforts and have a phenomenal weekend car. Loads of people are making upwards of 1,000+ on voodoo motors and loving it, but any dedicated drag GT350 is just asking for pain, IMO.
 

CANTWN4LSN

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Mod discussion aside, any day I want to start with a good laugh I just pull up and reread the metaphors in OP's original post. :clap:
 

MAGS1

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I did not get my 350 for the drag strip. Drag racing a GT350 is dumb: the clutch will literally explode, the TR3160 does not like gorilla shifting, there is no low end torque, and the suspension is tuned for the compete opposite of that. Sure, you can make a GT350 a fast 1/4 mile car. But that is not my goal.

I am modifying Mine to be a quick street car. PD blower coming to fix the torque and then I retain all the creature comforts and have a phenomenal weekend car. Loads of people are making upwards of 1,000+ on voodoo motors and loving it, but any dedicated drag GT350 is just asking for pain, IMO.
Yep I think you’re in the majority there. GT’s and GT500’s are better for straight line IMO. As we have both said, not that you can’t make a 350 a fast straight line car, but you’re going to be throwing a lot more money at it. A Whippled (or your blower of choice) 350 sounds like an absolute riot
 

Inthehighdesert

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My pump gas tuned whippled 350 would have pulled my 500 every where but the hole. But 50-60 to 150 plus was no joke. And the 500 is a beast from a roll.

Yep I think you’re in the majority there. GT’s and GT500’s are better for straight line IMO. As we have both said, not that you can’t make a 350 a fast straight line car, but you’re going to be throwing a lot more money at it. A Whippled (or your blower of choice) 350 sounds like an absolute riot
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