[dataway]

Mike .... can you tell me when you ordered the system? Just wondering which direction their quality might be changing.

I'm pretty sure they don't make the systems themselves .... I wonder if they use more than one supplier.

[SR-71]

The mufflers in the Inline Tube system are made in Canada and sound awesome!

[dataway]

System came in today. Looks good so far. Very nice bends, much better (or at least less distorted) than OEM. Nice finish on the pipes, hardware kit looks good. No dents, scratches etc.

Will spend the next week seeing how they fit.

[dataway]

I have questions and I have pictures

1. Longest muffler goes on the right?

2. Should Inline have sent me SIX 2.25" clamps? I only got FOUR. 2 at the front of the muffler, 2 at the rear of the muffler, two at the tail pipe. I did get 2 tail pipe extension clamps it appears ... the slip of paper shows them used to hold on the chrome extensions. Don't really look heavy duty enough to be the main tail pipe clamp .... but the Assembly manual does show a similar looking hanger/clamp used on the tail pipe.
(update: I think I answered this one ... evidently the tail pipe clamps and extension tip clamps are the same thing with different coatings, so I do have enough clamps, just have 2 of them in the wrong place).

3. I came across some stripped hanger holes ... used some SS 5/16" hardware instead of the OEM tapping screws. On the hangers out back ... can you reach the inside of the frame rail after the fuel tank is installed? If so great, I can use my hardware, if not, I'll have to come up with a different solution ... perhaps a rivet nut.

4. Should I use sealant on the joints? If so, any suggestions?

5. Look at the photo showing the Left side muffler hanger ... I had the brake line clamp in that screw hole ..... where should that brake line clamp go instead? The small hole above the muffler hanger bolt? The small hole over in the corner close to the frame? (OG68 I see you routed the line above the hanger hole and clamped the brake line at the small hole in the corner.)

Could you folks take a look at the photos and see if anything is really off base? Of course everything still needs adjustment, I only have the tail pipes installed. Are the tail pipes inserted into the muffler hanger about the right distance?

Thank you.

[OG68]

Item 1: Short muffler pass side
Item 2. Take a look at the tail pipe clamp photo. Only one large sheetmetal screw clamp.



Item 5: Before and after photos of brake line clip and location






If you closely look at the assembly manual specs it gives the dimensions of how far the muffler goes into the tailpipe. The originals had a small dimple as a guide

Have lots of photos IRT the exhaust installation. Nothing has been tightened down yet. Waiting for the engine install.

[dataway]

Excellent, thank you .... I've got the wrong clip on the brake line, and in the wrong location.

Looks like they sent me the wrong clamp for the tail pipe ... same clamp but wrong coating, should be phosphate like yours. I'll use what they sent and deal with that later.

Will correct these issues today, thanks again.

PS. Why do they use two different size mufflers?

[dataway]

I've got about an inch ... maybe 1.25" clearance from the pipes to the drive shaft on either side ... normal? Doesn't appear they would ever contact each other in normal use.

Do auto trans cars also have two different sized mufflers arranged the same?

I'm installing a manual trans system on my auto trans GTO since I didn't want the resonator pipes .... so far I don't see any problem ... but there are other small differences between the two.

So far the closest interference I'm seeing is between the left side muffler and the manual trans suspension brace .... won't know exactly how bad till the day the body is down and I adjust the tail pipes .... but right now it's about 3/4".

And ... what are these four bolts that came with the kit for? Pipes to manifolds?

[OG68]

From Brad Yost 6/21/2012

Upon doing a little searching on the internet about exhaust drone I found 2 things that people are praising to stop it. One of the things Pontiac did on the production line and I could never figure out why one muffler was longer than the other on dual exhaust Pontiacs and now I seem to have stumbled upon the answer.

If the right and the left sides are different the sine waves don't amplify as they are not the same frequency, so Pontiac engineer in their wisdom made the mufflers different lengths and sizes so the sound waves didn't mirror each other. It also seems that X pipes make this phenomenon worse, just switching one muffler may cancel out the drone.


__________________
Brad Yost
1973 T/A 4 SALE (SOLD)
2005 GTO
1984 Grand Prix




I've noticed that IT sells two different finishes for the rear exhaust pipe hanger clamp.

I had five bolts for my exhaust manifold clamps, but then again I'm using RA manifolds. So my guess is the same as yours in regards to the four bolts..

[dataway]

Thank you, you are a wealth of exhaust knowledge

[68ragtop]

I have an older gardner system on my car. I think one of the things that changed over the years is the clamps & the hangers. I think the originals had a hump in them between the threads on the u-bolt. I think I saved pictures somewhere. Mine are flat & my tailpipe hanger clamps are silver. Not correct, but how they were made 16 years ago I used a clear silicone that came with the kit & only tightened the muffler clamps until things snugged together. Just incase I have to ever take it apart again for some reason. I can take some pictures of how close the head pipe are to the drive shaft. I think you will gain room though once your suspension is compressed?

[68ragtop]

Originally Posted by dataway

And ... what are these four bolts that came with the kit for? Pipes to manifolds?

I am thinking catalytic converter..... jk

[68ragtop]

Just took a peek & I actually have a lot of room next to the driveshaft, but only about 1-1/4" from the floor brace. Looks like my pipes cold have been closer to the driveshaft for a little better fitment? Not sure. I can take some pictures tonight. But, again mine is a 16 year old Gardner & they might have changed them some. Kind of funny how even now there are "correct original" things changing on these cars that are over 50 years old.

I know when I paid up for that system it was supposed to have been made from either the original cards, or original pipes. Really don't recall, but Gardner was the only player for something replicating the orignal stuff back then.

[OG68]

Originally Posted by dataway

Thank you, you are a wealth of exhaust knowledge

Aw shucks...

My problem is that sometimes my memories of how the car was 50 years ago don't always jive with the facts.
Somethings I have photographic evidence of which help.

For the last 10 years of my previous job before I retired, I was the rail vehicle project manager for a transit company. I wrote contract bid specs for vehicle overhauls and modifications as well as maintenance procedures for our mechanics. I also directed the restoration of two 1946 vintage rail cars. To do all this I did a lot of research especially for the two vintage cars.
A major requirement of my job was attention to detail which help in restoring my 68. If I can help others with the information I dig up that's great.

There's a lot I don't know and people like Brad Yost, Peter Serio, and others plus the group of 68 owners add to my knowledge. I must have 40 subscribed threads with the knowledge of those that have been there and done all that.

[dataway]

I always take too many "after" photos and not enough "before" photos

I bought some Permatex Ultra-Copper RTV .. good to like 700 degrees, which Permatex recommends for exhaust systems. Will try that ... don't want anything that hardens like most of the exhaust "sealants" out there.

I have a feeling the factory probably changed exhaust system parts and designs more than just about anything else ... so commonly replaced back then, easy to work on, easy to fix and probably generated their share of customer complaints.

I noticed the Inline clamps have the hump in the clamp, but it's smaller and just there for looks, not like the originals where it was obviously for strength.

I'm tempted to oil up the slip joints a bit for the test fitting ... kind of a pain trying to adjust things without it ... I guess I could clean them before putting the sealer on.

[ddcrank]

Gardner Exhaust. I recently installed this Exhaust from Gardner. I was very happy with fit and finish

[Greg Reid]

Wow, I think that's the first restored car I've seen with the original style '68 exhaust, that is, with the 'resonator' stubs spliced into the tailpipe.

[dataway]

I remember when I was a kid and bought my GTO used in 1976 .. first time I looked up under and saw those things ... I'm like, what the heck are those, can't wait to rip that crap off Now all that "crap" is costing my lots of money to replace

Got my system in place, loosely bolted, all looks good so far. I do have some observations.

Is it just me or is hooking up the pipe to the left side manifold a pain in the butt? One of the studs was just too long and I had to trim in down in the lathe. They were aftermarket SS studs with the brass nuts. And it's all very close to the lower control arm pivot.

The muffler hangers are awful hard to tighten with the nuts on top and no room to get a ratchet and socket between the clamp nut and the rear cross member.

I assume the factory figured that most clamps would be just cut off when the system was replaced? Is that why all the clamp nuts are on top, or was it just to be a pain in the ass?

I'm waiting for the sealant to get here to tighten things down a bit more .... as nice as these joints fit I'm not sure if they even need any.

[68ragtop]

Would like to see some close ups of those resonators, clamps, hangers, etc.

Forgot to take pictures of mine, but its kind of the same story. I will say the fitement around the gas tank straps is snug. If I was to do mine over, I would have left the tail pipes loose & not final tightened until I had the body & fuel tank/straps installed. Not a big deal, but just something I realized as things where going together. Just add that they are loose to your check lists.

[ddcrank]

It really hangs nice under the body also. I had no issues with the fit.

[Greg Reid]

Very, very NICE ddcrank.