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Exhaust help and header gasket help.

3K views 32 replies 9 participants last post by  The Cub 
#1 ·
Hi guys so I need some help. Next week I might be working on the gt and as some off you know from my thread of working on my gt I got a header for my gt. Do I need to by a gasket off ogts for it?

Also I am going to do a 2 inch exhaust and probably put two glasspacks on it that my grandpa has. They are 2in inlet and outlet. We might take it to some one and have the part that goes over the axle and the tailpipes custom bent. Do you guys think this is a good set up?

What exhaust did you do and post your videos of them too. My gt is really quiet with one muffler and no resonater.

Thanks Sam
 
#2 ·
Gasket yes this would be favorable.
1 glass pack will be plenty I don't think 2 would fit #1
I have one on mine and deleted the resonator and ran it straight back for now until I can get the piece that goes of the rear axle in a 2"
I also (well my son) put a large resonating tip at the end that he can adjust back and forth to get the desired tone he wanted and as he says the throaty popping when down shifting
 
#3 ·
Ok I will order the gasket, Hopefully it comes by next week.
Do you have any videos of you exhaust? We will probably only put one glasspack on it but if it is too loud we will put to.

Sam
 
#4 ·
no video's but a couple pics of initial/temporary set up to judge sound and whether we wanted to go in that direction or not.
notice it is temporarily ran under the rear axle. this will be rerouted above axel and to it's original spot when I figure out how to bring it out to 2 exhaust tips to mimic the original resonator.
I was surprised at the sound and tone improvement from the original stock set up. My son was on to something here lol
hth
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#5 ·
What tip did you use? And where did you buy it?

This is what my gt looks like since it has no resonater we are going to try to replicate this with the 2 inch exhaust.
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#11 ·
I believe it was off the shelf at auto zone or advance they didn't have what I was looking for at the time but once we got it hooked up it was fine.
It is adjustable from 3" to 1,3/4. Nice that it can be adjusted to sound how you want it.
Nice Terry. If it were mine Is mount it where the original was.
Hi guys so I need some help. Next week I might be working on the gt and as some off you know from my thread of working on my gt I got a header for my gt. Do I need to by a gasket off ogts for it?

Also I am going to do a 2 inch exhaust and probably put two glasspacks on it that my grandpa has. They are 2in inlet and outlet. We might take it to some one and have the part that goes over the axle and the tailpipes custom bent. Do you guys think this is a good set up?

What exhaust did you do and post your videos of them too. My gt is really quiet with one muffler and no resonater.

Thanks Sam
Yeah Sam, you need a gasket for it. OGTS should have one. Do a search here on the board about exhaust gaskets. I was always told when using a header to get the gasket wet, (as soak it in water) put it on, fire car up, run it about 15 min, retorque the intake/exhaust bolts. I believe the header will bolt up nicely. It will be loud without any rear pipes on it,
 
#12 ·
Hi guys so I need some help. Next week I might be working on the gt and as some off you know from my thread of working on my gt I got a header for my gt. Do I need to by a gasket off ogts for it?

Also I am going to do a 2 inch exhaust and probably put two glasspacks on it that my grandpa has. They are 2in inlet and outlet. We might take it to some one and have the part that goes over the axle and the tailpipes custom bent. Do you guys think this is a good set up?

What exhaust did you do and post your videos of them too. My gt is really quiet with one muffler and no resonater.

Thanks Sam
Hey Sam, you may want to reconsider the glass pack muffler - without AC your windows will be down in the summer and while the glass packs sounds really cool, I have a feeling you may be looking for a more quiet ride so that you can hear your sound system and so you can hear what your passenger is saying . Also, not sure you want to go to a 2 inch exhaust for the same reason unless you are going to build the engine - again makes the car louder. But that is just my two cents worth as I recall at 17 I put dual exahust on my Mustang with glass packs. However the difference in sound of a 289 V8 and a 1.9 4 cylinder is well, you know. Good Luck.....Carl
 
#13 ·
I don't really care about the sound system so that isn't a big deal but My grandpa haa a complete roadmaster radio with speakers that we are going to install. If we think it is too loud we will put maybe a mg midget muffler on that my grandpa has laying around he also has a resonator from a triumph spitfire so we will see if it is too loud.

Also last night I ordered the exhaust tips and my grandpa ordered the gasket so hopefully those should be in by friday since I have fall break friday to monday. We will hopefully get the exhaust done through that time period.
 
#16 · (Edited)
( Will I Finish) so that you can hear the sound system

And there is the down fall.
We built a custom sound system for ours and realized you can hear the highs fine but the rest is drowned out coupled with an alternator which doesn't have enough ump to drive the sub/both amps and since I didn't want to destroy the dash putting the head unit in ( or spend the money on one that would fit/look more time period correct) I incorporated into the box we made. That's mistake # 2.
The only good that came out of all this was you'd never know there were 2 amps stuffed back there and ALL the wiring is completely hidden.
Now mistake #3 This added at least another 100 lbs or more. 1 plus is, by design I can have the whole unit out in 5 mins including the amps, 1 is attached to the box the other on the shortened custom spare tire shelf made just for the other amp. Yep it coming out permanently once we get to redoing the interior.
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I don't really care about the sound system so that isn't a big deal
That's what I'm talking about, it becomes a distraction anyway from the vroom vroom
Which makes me smile much bigger than boom boom
 
#17 ·
I went with a stainless steel system. Stainless has a deeper throatier sound.
On the contrary. A harder metal will sound ‘tinny’. So mild steel will be deeper sounding than stainless steel. And titanium will be VERY tinny sounding. Thinner gauge metals will sound even more tinny.

Tubing diameter matters too, as does engine displacement.
 
#18 ·
You can spend quite a bit of money on your exhaust system and there’s not much wrong with that. I had a muffler shop redo my exhaust 5 years ago and he put this performance muffler on its straight through and it’s packed with stainless steel, not glass packed but has a very throaty sound.
Just ask Carl who took a drive in it last week with me, it’s plenty loud when you are on the gas. If you’re like I was back then loud was fun.

This particular muffler comes in at half the cost as the top quality ones but has good construction and with the reasonably priced Hedman chrome resonator tips gets the job done. I got the muffler shop to weld it in with the 2” exhaust (I went 2 1/2” over the rear axle). If you’re spending the money, some good advice Gordon gave was to have another flange installed right before the muffler pipe goes over the rear axle. This way you can remove everything and transfer your investment to another GT if you pick up a better one in the future.


I have a suggestion. Click on this link and see post #29 to see what I did
 
#20 ·
My exhaust is super simple. No mufflers, 2” pipe and long tube headers to the factory resonator. It’s plenty quiet when cruising, it nice and noisy at full throttle.
I can still hear my stereo just fine and they are just 2 little 6” speakers in the rear.
 
#21 ·
Do you think a glass pack would sound like your car? I have heard your car on YouTube and I really like the sound.
 
#24 ·
I got the tips in the mail yesterday. They look a little big but I think they will work great and they were cheap!

Sam
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#31 ·
One thing to make sure of with older unknown headers for Opels, is that the mounting flange thickness is correct. A lot of those older ones on the market were badly made.

The header flange thickness that is adjacent to the intake manifold MUST be close to the same thickness of the intake manifold (which is 12 mm thick, or .472”). If it’s not within +/- .025” of this thickness, you will have eternal issues with exhaust leaks, blown out intake gaskets, or intake (vacuum leaks).

A lot of those older headers were made from 1/4” or 5/16” steel with half washers welded on, but they were often still off by 1/8”!
 
#32 ·
I think this is it at ogts
but I did not see the joining flange listed ( doesn't mean they don't have one)
Nor the bolts but you may ask Gil
You might even take it to a muffler shop and see if they can match one up for you if ogts can't help you
 
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