# 2005 6MT newbie help



## shadowsonic (Nov 8, 2018)

I'm brand new to this vehicle just sold my 03 mustang cobra can someone guide me in the right direction, for mods I'm looking for the best setup for headers, underdrive pulley, catback system and cai. I live in Boston,MA inspections are hell here i want a nice sounding car not an obnoxious fart can. 

Long tube headers or shorty? I've found some nice high flow cats but finding alot of the items on e-bay is quite a hassle. 

I just bought a 2005 GTO 6MT with 29/K miles just looking to squeeze some hp out of this and find a tuner to dyno this thing, any help quite appreciated thanks.:grin2:


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## shadowsonic (Nov 8, 2018)

anyone just looking for best brands to use and so forth.


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## Shake-N-Bake (Jun 16, 2015)

When I bought my 05, I searched and searched for a car that was un-molested or very lightly modified. Many others on here are likely to have a similar mind set.

A good forum to talk about modifying these cars is the LS1GTO forum. They speak LS2 also....

Shorty headers are a waste of time....that is pretty much what came on these cars originally so not much improvement IMO. If you want the headaches that come along with having headers then long tube is the way to go.

Good luck with your mods. Am not knocking your intentions....I was the same way back in the late 80s and early 90s. I couldn't wait to modify my cars to suit my tastes. 

These days I want a car that can run high 12s in the 1/4 mile, light up the tires with a flick of the throttle, get 20 mpg, cruise with A/C and shift manually. I get all that and much more with my 05 so I am happy to leave it as designed by the factory. 

Check out the LS1GTO forum. You will find answers to your questions over there.



Sent from my SM-G930V using Tapatalk


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## shadowsonic (Nov 8, 2018)

Shake-N-Bake said:


> When I bought my 05, I searched and searched for a car that was un-molested or very lightly modified. Many others on here are likely to have a similar mind set.
> 
> A good forum to talk about modifying these cars is the LS1GTO forum. They speak LS2 also....
> 
> ...


thank you ill check it out most of the gto forums don't have a much activity.


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## Bill S (Apr 16, 2005)

Yeah, the activity on LS1GTO has died down.
Modding the GTO definitely picks up power, but be prepared to have a healthy budget. It is best to research build options and then reflect what is realistic financially.
That said, a cam swap, long tube headers such as Kooks with cats, an over the radiator air intake like the Svede if you find one or the one from New Zealand work best. Select a cam with high lift but don't go crazy on the intake duration. Add underdrive pulley. Then get it tuned. If you have a bigger budget, porting the 243 heads pays off.
Is your budget is greater, a TVS supercharger is the ultimate.


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## nardulli (Sep 13, 2009)

I replied to a similar question here: https://www.gtoforum.com/forum-index.php/#/topics/132883

There are photos on that thread that might be helpful. 

I have also shared the complete factory shop manual on this forum as well. I found it super helpful. 

In addition to what I wrote in the post noted above, the LS2 in these cars has a 90 mm throttle body / intake manifold. I’m presently researching whether or not there is a more free flowing intake available. Maybe something from the corvette line. 

I’ve had two of these cars. Both 06. (Same as 05). Made some mistakes - especially in exhaust. With long tubes, and 3” pipes, it’s a struggle to get the sound right. Tried Borla. The Attack model is way too obnoxious. The touring option was better. Magnaflow were hideous. Finally found a small shop in Toronto that made custom glass pack mufflers for me that are amazing. Hard to describe. Not a lot louder than stock while tooling around- deeper sound. But put your foot in it and holy hell they sound great. Guy only charged $300 for the pair, delivered. 316 stainless. Photos on the other thread. 

It’s a great car. Have fun. Feel free to pm me if you need anything.


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## shadowsonic (Nov 8, 2018)

Thank you ls1gto is dead! I still can't post anything there and this was the only forum besides youtube videos that have info on this vehicle.


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## shadowsonic (Nov 8, 2018)

Bill S said:


> Yeah, the activity on LS1GTO has died down.
> Modding the GTO definitely picks up power, but be prepared to have a healthy budget. It is best to research build options and then reflect what is realistic financially.
> That said, a cam swap, long tube headers such as Kooks with cats, an over the radiator air intake like the Svede if you find one or the one from New Zealand work best. Select a cam with high lift but don't go crazy on the intake duration. Add underdrive pulley. Then get it tuned. If you have a bigger budget, porting the 243 heads pays off.
> Is your budget is greater, a TVS supercharger is the ultimate.


Kooks 3/8, Kooks midpipes, Magnaflow x-pipe, Magnaflow mufflers, Svede intake MGW-P short shifter
Koni Yellow Shocks/Struts
Lovells 330mm/350mm Drop Springs
Hotchkis Sway Bar and Anti-Roll Bar
Roadsafe Bushingless Sway Bar Endlinks
Whiteline Poly Strut Bushings
Whiteline Poly Shock Bushings
Whiteline Poly Differential Support Insert
Whiteline Rear Cross Member Bushings
This is so far the best setup i've found. Don't want to play with cams or porting out the heads i want to enjoy the car without going crazy on it and risking not passing state inspections.


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## shadowsonic (Nov 8, 2018)

nardulli said:


> I replied to a similar question here: https://www.gtoforum.com/forum-index.php/#/topics/132883
> 
> There are photos on that thread that might be helpful.
> 
> ...


What didn't you like about magnaflow? I want something a little louder than stock but nothing like a slp, corsa, or some test pipes i don't want a fart can coming down the street something nice classy but with still a nice growl.


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## nardulli (Sep 13, 2009)

The Magnaflows were the worst thing I tried. SO loud at all RPM and terrible drone while cruising. Plus a lot of ugly noise on decel and between gears while shifting. Still annoyed the neighbors while trying to creep out of neighborhood in the morning. With long tubes and an H pipe, you have no room for resonators. Get in touch with these guys: Mufflers | Cortek Exhaust Systems 

They will custom make you a set of glass pack mufflers for $300 delivered. I've posted photos elsewhere here. Truly great guys there.


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## shadowsonic (Nov 8, 2018)

nardulli said:


> The Magnaflows were the worst thing I tried. SO loud at all RPM and terrible drone while cruising. Plus a lot of ugly noise on decel and between gears while shifting. Still annoyed the neighbors while trying to creep out of neighborhood in the morning. With long tubes and an H pipe, you have no room for resonators. Get in touch with these guys: Mufflers | Cortek Exhaust Systems
> 
> They will custom make you a set of glass pack mufflers for $300 delivered. I've posted photos elsewhere here. Truly great guys there.


I'll look into different exhaust thanks for the tip for now i'm trying to stay with one full catback versus going with piping and building an exhaust.


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