WARNING: Very exhaustive post ahead. (I'm not kiddin!)
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Tip#14: Fitting a 3.0" inch exhaust is no picnic. To make your life easier, cut out the 47 year old sagging floor, build the exhaust, and then weld in a new floor. Its quicker in the long run.
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Yeah, its a big car, but that's also a big pipe to get by a 9" rearend, upper control arms, coil springs, and shocks. Plus it all has to line up symmetrically when complete, not bang around on the floor or frame or leak. That's a lot to ask.
I just looked through 17 years of pictures I've taken of this car and none are specifically of the exhaust. I don't even have any of the final mounted system for this build. I had to go take some.
Why? Likely because I'm never really happy with it - its just something that has to be there and was just "good enough" to not annoy me. Its not the quality of the parts chosen, its the fitment. Its always a compromise. I get it, I'm asking a lot of this chassis to hide pipes it was never designed to hide, but I'm tired of compromising, so I was determined to get this fixed this time around.
Most midsize car chassis are expecting their exhaust to share space in the driveshaft tunnel while the mufflers tuck up nicely into the recesses designed in the floor. That's all well and good if you're running the stock 2.25" duals. They'll fit just fine. Now get an 3" X pipe to fit by the humps of the trans cross member. It wont. Try getting two 3" pipes to share room in the trans tunnel with a 3" driveshaft. They wont. And now, because you had to pull of those pieces so far down to clear the floor, the muffler will never come close to sitting up in that recess specifically made for it. Finally, because the muffler now hangs down so low, the tailpipes are lower than the should be and don't line up with anything, except the 9" rearend, upper control arms, coil springs, and shocks. (OK I exaggerated - it clears the shocks) The domino effect is extensive, but thankfully the fix is simple.
One of the key points of any good exhaust, is where the headers "dump" you. They set the tone for the X pipe to either fit up tight, or hang down low. I don't know how the header builders do it, or what rule of thumb they use, but these JW pieces set me up to sit up nice, tight, and level; just how I want it. If you ignore the trans fluid on the floor, (stupid drain plug) you can see it in this pic - the bottom of the header is almost perfectly in line with the trans pan. (The only reason it likely isn't 100% level, is the shims at the trans mount helping me achieve proper u-joint working angle)
Here is a good shot too, but I'm getting ahead of myself here -
In case anyone needs to know, the system behind those headers will be a duplicate of what Ive run on this car ever since they started making them - Pypes 64-74 A-Body 3" Crossmember Back w/X-Change System. The mufflers are 20 inch case Magnaflows.
BTW, If you like numbers, it takes 4 jack stands to level the car. Two more to hold up the X (if its connected to the header, 4 if not) and then if you're good, 1 for each muffler. (2 if you cant connect them to the X). Now try navigating around on a creeper.
I built these to help me get the height I needed to roll around under the car with ease. Doesn't help with the mockup just yet, but they allowed me to get rid of the stands holding the car level. (They will prove to be useful for many things going forward.) Oh yeah, I hung some fenders. And had to put on wheels. And I ran a wiring harness. And painted me fender supports.
Life is good. I wish I made these a long time ago. Now we can get back to the actual exhaust.
Here is the secret sauce to all my woes. These will take all that hangs low and bring it up again.
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Fun (like makes you angry fun) Fact: In looking up this part number, I see Pypes now has a high tuck setup, similar to how I solved my problem. Son of..... Twas not an option when I bought. And the whole time working on this I was thinking, how can a company that sells 3' exhaust, not be thinking about how much they hang underneath these cars? At least they're paying attention. Well played Pypes Peeps. Well played.
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Since I didn't know where the X was officially going to end up, I asked my header builder to make an extension I could cut to length when ready. The Vband connector was mandated by me. I'll rant about 3 bolt flanges later.
And we gotta have some fun, right?
These QTP cutouts came highly recommend and I dig their low profile. What I don't dig is the cutout for a 3" system only has a 2.5" butterfly. WTF? Just keep that in mind if you're looking to buy. I guess it still beats carrying that 9/16 to undue the caps, right?
They also come with their own pre-wired switch and factory terminated wiring. You cannot cut the wiring to fit or you void the warranty. With the amount of wire given, I could mount the switch some where near the radiator I think.
I swear, I do NOT work for this company- they just make good stuff.
Mix all of these pieces into a paper bag, and this is what you get. (notice how much I had to reshape the sagging floor pan to avoid having any contact)
It takes a certain level of talent to get these cutouts to be parallel to the ground the way they are. Especially since each exhaust piece you cut splice and weld has an angle, and any turn from its original location, will throw everything off down the line. I do not posses such talent, so I whittled out the bolt holes on the cutout so I could clock them correctly.
If you've never done a 3" pipe in one of these cars, (or any older GM muscle for that matter) it'll be tough to appreciate the effort involved in making it work. I can show you a ton of pictures, but they'll never capture the time it takes to get those tailpipes to fit. They'll also never allow you to see how much higher this kit sits up from any of the ones I ran previously, but that's probably because I never took any pictures.
There, and I even saved you a rant on 3 bolt flanges. Youre welcome.