Best Exhaust system for '91 GT 5.0?

[Cenla 5.0]

What is the best exhaust system for the stock '91 GT 5.0? I will be replacing the stock system soon (real soon!) and have it narrowed down to the Flowmaster and the Mac. Money matters so it will be under $300 or so, strictly a cat-back system. Stock, this GT saw 155 mph on Interstate 49 late at night!

Would appreciate your opinion!

[lx mike]

You was doing 155 mph in a "stock" mustang gt?? whats you definition of stock?? if you had a cobra i might beleive you but not a stock gt your about 10-15 mph too optimistic

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93-LX: 5 Speed, Flow's with H-Pipe, 3.73's Sub's and K&N.

[92FiveOh]

The Dynomax is a decent setup for under 3 bills. I even saw a $25 rebate offer in the latest Jegs catalog.

HTH, Larry
'92 5.0 ; Paxton Sc

if you plan to keep it basically stock, which it appears to me that you are, then I would just change the mufflers. I'd get some flowmasters and let it ride..

[Unit 5302]

I'd call Summit Racing and check the price on their DynoMax Super Turbo Catback for the 1991 GT. They don't advertise it in the magazine, but they do stock it. When I found that out I was ticked, I paid too much for mine. Summit's Price was $169-179, forgot which.

Quality on the Dynomax is excellent. I've NEVER heard a bad comment on the fitment of their exhaust products.

[93CobraR]

Thats funny, doesn't your speedo only go to 140? Get the Flowmasters....

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87 GT, 4 inch cowl hood,17x9 Cobra R's/255/45's,GT-40 heads,Crane 2031, Edelbrock intake, long tubes headers,h-pipe,Flows,BBK cold air, Mass air,70mm MAF, 1.7's, 1" spacer,underdrive pulleys,Pro 5.0, King Cobra, Adj. fuel Reg., Lakewood Lift Bars,50/50's,subframes, 4.10's.
Best time 12.96
Best MPH 103.42
Best 60' 1.695

Visit my site at:
http://www.geocities.com/cobrar93_2000/MyPage.html

Originally posted by Unit 5302:

Quality on the Dynomax is excellent. I've NEVER heard a bad comment on the fitment of their exhaust products.

Well, that price seems good but... I got a new one for ya. I've got nothing but mac exhaust and my opinion of their stuff isn't that good. To quote my mechanic "Man, your exhaust is a basket case!" This I know.. mounts in stock location my @55! I have my cat back hanging by some homemade hangers. The cat h-pipe never did fit good and always leaked.. the headers seem ok tho.. The newer mufflers I can't speak for but they look like Flowmasters to me, welded and all. If you think the super turbos are good mufflers then just sit a pair down next to some flowmasters and your opinion will change real fast.

[Stang Runner]

I hate Flowmasters It had a bad drone when on the freeway. They rust look bad! Get any stainless one. I have elderbrock they are loudest street one out there when Accelerating. But not as loud a Flowmasters when it is at an idle. It has alot more flow, might not be all good.

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1988 LX 5.0
Drivetrain: 2.73 Stock Gears, World Class T-5, Lakewood Bellhousing, Summit Adjustable Cluch Quadrant & Cable, Alumminum Driveshaft, Flaming River Manual Steering Rack
Suspension: MAC Control Arms,Maximum Motorsports Front Grip Package, H&R Sport Spings, Bilstein Shocks
Engine: Steal Mounts, Ram air, K&N, Under Drive Pulles
Exhaust: 1 5/8 Un-Equal Length Mac Headers, X-pipe W\cats, Edelbrock cat\back

[90dpscoupe]

Yea, your speedo goes to 140, unless you have a police car, or highway patrol (160) or some aftermarket steeda guage, or what have you.

Although im cofident a mustang can go very close to 150mph stock, but the speedo may not be exact.

Id get the flow.. 3 chbr mufflers, mine sound nice, not too loud, and when i put my h-pipe on, its gonna sound just mean enough.

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90 lx coupe: 175k miles, steeda water pump pully, hurst shifter, Mac cold air fenderwell, accel supercoil, ADS chip, aluminum D/S, Black magic fan, 3.27grs.
Best time: 13.9116(on 225/60/15 firehawks)
Best mph: 98.17
Best 60': 1.9607

next mods: subframes, mac h-pipe

[1BAD89]

Stock 89-93 stang around 140mph. My 3 chamber flows sound awesome especially with my off-road H-pipe. The Force II cat back kit is $265 in jegs, and the American Thunder 2 chamber kit is like $226.

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3:55's,BBK Off-Road H-pipe,BBK jet-hot coated equal length shorty headers,BBK 70mm Throttle Body,BBK adjustable clutch quadrant,C & L 76mm Mass air meter,Cobra R's 17x9 w/ 245's,Trick Flow Intake,Flowmaster Force II exhaust system, Super Duty T5,Centerforce II Clutch,Heavy Duty Radiator,9mm Ford racing plug wires,Accel cap and Rotor

www.geocities.com/i8urvpr/JM.html?987369348700

[QuantumMotorsports]

If I were you, I'd go to a muffler shop and see how much it will cost to weld in two flowmasters. 40 series two chamber. It's the only way to go. And if you really want it to sound good and drive better, you need an offroad H pipe. I've got 2.25 inch H pipe, no converters, two chamber flows, and 3 inch turn down tips right behind the mufflers. Sounds great. I left my tailpipes on, and had the muffler shop weld the turn downs on with plates so I can bolt them up. I'm not even joking when I tell you I went 15.0 with the plates on, and 14.6 with them off. Turn downs help!!!Anyway, just my opinion.

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Michael Black
Quantum Motorsports
Norman, Oklahoma

1988 Merc Cougar 5.0 HO, Ported and Polished E7TEs, 2.25" offroad H pipe w/ 2 chamber flowmasters, T5 tranny
New E/T!!!
14.626 @ 94.94mph, 2.194 60' time, a little better than last time. Keep in mind this thang is heavy (3590lbs) Finally 14s!!!!

[SaleenGTS]

Road and Track tested a stock 87 GT with the 2.73's....it ran 148, but also noted that the speedometer pegged out after 140. 155....maybe with a 180 mph tailwind. The new Cobras don't even go that fast, and wven the 93-97 LT1's only hit 157. sniff sniff, you smell somethin?

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Dustin
90 Saleen yup, got her back!!
89 GT (Saleen clone)392 rwhp UNTUNED(TFS Intake, spacer,Heads and #2 cam, BD-11A 9#(only boosting 6???WTF),1.6 rr's,BBK 70mm TB,FMS 70mm MAF,MSD 6BTM,FMS 9mm wires,BBK longtubes and H-Pipe,American Thunder cat back,3.55 lots more...

12.564@118.49 on street tires is my best so far. Still untuned

[DemonGT]

i have full Mac exhaust and have no complaints..no matter what brand you get it isnt going to be a piece of cake puting on specialy long tubes..but i think the sounds is awsome...some ppl complain but the fit of the mac stuff but mabe they just didnt put it on right

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'91 GT,91K,T-5,air silencer removed,racing clutch(previous owner put in so dont know what kind),K&N air filter,Mac long tubes,Cat-back,off road H,FMS 9mm wires,Competition gauges,C&L 76mm MAF

Future Mods:3.73's,Pro 5.0,accufab 70mm tb,TFS heads,TFS stage 1 cam,lakewood struts/shocks,nitto DR's,four cylinder springs up front
ICQ#35670781

For a MAC system, headers on back......what should it cost? I've heard the whole system will be about $1000. True?

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'90 LX 5.0; 12K original miles (no sh*&); 3.55 gears; pulleys;Edelbrock Performer Heads; BBK shorties; MSD 6AL box w/ blaster 2 coil; Motorsport E303 cam; Pro-M 75mm MAF; BBK 70mm TB; Eibach spring kit; Southside welded subs; K&N cone filter charger; Hurst shifter; fiberglass turbo hood; A/C-less; rear seat-less; cat-less; 2 chamber Flos; Corbeau racing seats (fronts);
30# injectors; JMS Chip; 190 lb fp; TFS track heat Intake (12.299 @ 113)

[Cenla 5.0]

My very first post to this Forum and I make a typo! It shoulda been 145 mph, NOT 155! Sorry... I can understand your skepticism.

I will go with the Flowmaster system. Thanks to everyone for their input.

Kewl site!

Regards,
Cenla 5.0

[JM90GT]

When I first got my 90 GT (140 on the speedo) I passed the 130 mark on the freeway and was closing in on the 140 mark fast when I backed it off. So.... I don't know. And mine was all stock. But anyway my buddy has a full Mac system (93 LX) and it sounds great, he paid just over $700. All I did was picked up some flowmaster 2 chamber muffs and had them welded in. They sound just as good but for the money I don't think I'd do it again. I was in to big a hurry for the sound and ended up paying $240 for the whole thing. I think I could have gotten a lot more for not muck more $$$. But thats just me, that's how I do things.

[dashapht]

I have MAC Long tubes and a pro chamber with Flowmaster 2 chamber cat back kit and stainless tailpipes. It sounds GREAT all around but drones a little (Flowmasters there). The mac stuff fits perfectly and doesnt leak anywhere. Same with flowmaster. If you want Mac, get it from www.mustangwarehouse.com Thats where i got my headers ($220) and Pro chamber ($220) and they were both shipped free. I got them within 4 days of ordering (NJ to TN). Since you have a GT you can save a few bones on stainless tailpipes. LXs look horrible without them though. Get long tubes, either an X-pipe or a Pro Chamber, and it's up to you on the cat back. just make sure it's all 2.5 inch. If you can, ride with people that have the different brands of mufflers to see if you want to put up with the drone of the Flowmasters or say the quietness of Dynomax. I quite happy with my system, but I think soon I'm going to try some quieter mufflers. I plan to go on some trips this summer and I dont want 10 hrs of 2 chamber DRONE. Know'm sayin?

Originally posted by DemonGT:
some ppl complain but the fit of the mac stuff but mabe they just didnt put it on right

At first this statement kinda ticked me off.. after thinking about it, I'm convinced it's the cat h-pipe that is the culprit. I have short tube headers because no one made long tubes for the aod when I purchased the exhaust. The h-pipe is a 2 piece unit. I had a pro put it on and I didn't like the fit so I was under the car until 2am one night trying to adjust it. My tranny guy has had it off a few times and said its a POS, he's been doing this since he was a kid. The mechanic I have now is about as good as you're gonna find. I think the 2 piece h-pipe is crap, I'll never own another. The super turbos are good mufflers and sound good, but the construction is along the same lines as stock. The flows are built better.. the new mac mufflers seem to be too. As soon as I can afford it I'll be buying Mac long tubes and off road h, they are the only co. that makes them for the aod(that I've seen). I'm only buying those because of the exhaust leaks that are driving me crazy, maybe with the new headers and h-pipe the cat-back will FINALLY fit right.

As far as your situation Cenla, I paid around $800 for my exhaust. If you don't plan on doing some massive stuff like add a blower, nos or build the motor... I'd buy 2 flows@$50 a piece and an off road h and have that installed. The prices vary on the labor, look around.. you will find someone cheap.

Thats all I have to say on this subject