Exhaust System Replacement

Tynan918

Royal Smart Person
Thread starter
Aug 2, 2021
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Never replaced manifolds, installed headers, or any exhaust parts...removed exhaust manifolds for a engine pull once and wrapped headers before, but that's it when it comes to the exhaust system.

Should I buy the parts and have a shop install them (how much ?) or just install everything myself

Starting with the manifolds first...

Headers or OEM manifolds? If headers, can you give me examples or specs as to what I should be looking for while shopping for headers ?

IMG_20220910_165323997.jpg
 

ck80

Comic Book Super Hero
Feb 18, 2014
4,547
113
Never replaced manifolds, installed headers, or any exhaust parts...removed exhaust manifolds for a engine pull once and wrapped headers before, but that's it when it comes to the exhaust system.

Should I buy the parts and have a shop install them (how much ?) or just install everything myself

Starting with the manifolds first...

Headers or OEM manifolds? If headers, can you give me examples or specs as to what I should be looking for while shopping for headers ?

View attachment 206795
Really it depends what you want, and, future plans to remove that 305 lump for a better engine.

If you're going to stick with it long term, I can point you to some 3/4 length headers that will have 02 bungs on them, but, are slightly uglier in that they have a.i.r. provisions you will need to stick a plug into running above the collectors on each side. New in box delivered runs less than $90 for the pair ordered online.

It all comes down to preferences. Doing it yourself? Could break off an exhaust bolt in the head and that's a good bit of time and effort to remove as a shade tree mechanic lacking the best tools. Sometimes more than one.

Your leak could be a symptom of such a break too, not keeping it torqued down.

No two of these cars is exactly the same. One guy says his header fits like a glove, the next guy needs to do some massaging with a hammer to clear a steering or control arm piece on the exact same header. Gm left lots of room in there for their manifolds so it didn't matter to them.

Depending what you go with, exhaust costs change as well.

Manifolds are the easiest to install, cheapest in labor and exhaust. Lowest performance improvement option.

Shorty headers, more work, most interference issues. Higher labor and exhaust.

3/4 length headers, easier install and exhaust connection than long tubes, lesser interference. But again, exhaust costs.

Long tube headers maybe higher performance option, but, more pain to connect and get exhaust lined up from under car on your back. Still needs exhaust.
 
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Tynan918

Royal Smart Person
Thread starter
Aug 2, 2021
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Well, the first logical queation is what are you wanting to accomplish here..
Well I have black soot on my driver side manifolds and my manifold to pipe donuts/setup looks ****ed.

I would like to change everything and possibly eliminate the exhaust ticking I have. Ticking could be a lifter on the driver's side as well...
 

Tynan918

Royal Smart Person
Thread starter
Aug 2, 2021
1,086
63
Manifolds are the easiest to install, cheapest in labor and exhaust. Lowest performance improvement option.
So I can change the manifold/headers without replacing the whole exhaust system, like exhaust pipes and mufflers and tips? Those things can come on a little after?
 

Built6spdMCSS

Royal Smart Person
Jun 15, 2012
2,148
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Florida Beach
So I can change the manifold/headers without replacing the whole exhaust system, like exhaust pipes and mufflers and tips? Those things can come on a little after?
Yes, if you're just trying to swap out Manifolds.

Where is the soot at? Sounds like the donut gasket went bad from what you're saying, that will definitely make noise.
 

ck80

Comic Book Super Hero
Feb 18, 2014
4,547
113
So I can change the manifold/headers without replacing the whole exhaust system, like exhaust pipes and mufflers and tips? Those things can come on a little after?
How much needs changing depends what all you have there.

From what I recall, your pipe flange at one of the manifolds is chewed up and no longer a smooth flared surface. So that needs to be dealt with, and, may not line up after I too much needs removing.

I dont recall if you have a y-pipe or already true duals. If a y-pipe, then headers cost you now in that you'd need to run exhaust behind it.

You could go with some L69 f-body manifolds, and upgrade to a larger y-pipe, converter, and intermediate pipe that would both sounds and flow better than a took, but, not as good as headers. But it is likely the best flowing stock gm manifold setup for a sbc that is gbody friendly since rams horn style manifolds get interference from the front crossmember/suspension. But that's money, and, if you sought headers in the future you'd be undoing all that work. Still, it's worth a few HP and ifna shop near you does custom aluminized pipes at a low cost per foot it might be worth it, especially if, as i said, that existing flange isn't easily salvageable.

Now... as for the exhaust leaks and soot in the pics you've posted a few times not near the heads, I doubt your stock manifolds are cracked or warped being the issue, so, a remove, cleanup, and reinstall should be an option.

Any headers will require some work on the exhaust. Doesn't matter shorty/3/4/long tube. How much depends what's currently in the car, if you've got true duals already, and what the collector size is vs pipe size under the car, you might be able to cut the existing pipes if true duals and connect the headers to it without doing full intermediate pipes, mufflers, and tailpipes. But if stock gbody exhaust is what's there now, no, it'd be a bunch of work to do any header.
 
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Tynan918

Royal Smart Person
Thread starter
Aug 2, 2021
1,086
63
Okay, we're going to start with the exhaust manifold gaskets...

I bought Mr. Gasket Copper Manifold Gasket set...
IMG_20220917_104934799_HDR.jpg


What are these rubber o rings that came with the gasket set used for ?

IMG_20220917_104940440.jpg


I also would like to replace the bolts and nuts that mount the manifolds do the engine. I know they're 3/8-16" in size and Dorman sells a kit, #03401, with the bolts but I'm not sure if the package is for just one manifold or both...🤷🏾‍♂️

Screenshot_20220917-110805-591.png
 

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