Truck Exhaust Question

pattersonj11

Old Mossy Horns
I have a 1997 4wd short bed Chevrolet. 5.7 engine.

My headers have holes around the inside of the pipes at the collector. I’ve tried to get it repaired and everyone has said they would have to cut it apart to possibly fix it. You can’t get to the leak area. It has gotten worse.

Now I’m replacing the whole exhaust. I’m going to replace the headers and the catalytic converter portion myself. After that, I will find a shop to handle the rest.

I need gaskets between the headers and the catalytic portion. Anyone know what kind I need. Seems they make the doughnut style and also the flat gaskets. Not sure which I need. Any ideas?
 

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nccatfisher

Old Mossy Horns
Contributor
If your headers are like the ones pictured it appears you need the doughnut type. Most of the headers I have ever messed with had flat gaskets where they bolt to the collector flanges. Are your cats a direct bolt up to that collector on the header or are you going to have to cut the pipe to the cat and weld it on the collector flange that bolts to the header?
 

pattersonj11

Old Mossy Horns
It’s a direct bolt up currently. I ordered the same headers.

Any idea if those can be found at about any auto store? I have flat ones coming with the parts, but didn’t know if I should order a set of doughnuts. May be able to buy some if needed whenever the process gets started.
 

Mr.Gadget

Old Mossy Horns
You ever done that work?
Set up for it with welder, ox torch and needed tools?

I know on the 89 to mid 90 trucks they used cast iron manifolds.
They were all prone to rust and broken bolts. Takes time, tools and a good head to get the studs and bolts off prepared for mounting new.

Also.may need to relocate other items for install. They are not prone to an easy unbolt and bolt the new up.
 

Mr.Gadget

Old Mossy Horns
Btw mine was a 89 k5, more room than newer trucks. Needed to lift motor to remove and replace, had to replace the motor mounts also, they went bad and reason for leaks everytime.....
 

pattersonj11

Old Mossy Horns
Gadget, if you put the hex on me we are going to have a battle royale.

I’ve never done a whole lot of it myself. I have tightened them up when a bolt backed out. I’ve pulled them with the help of a buddy when we were trying to fix the leak. That has not been terrible, but I wouldn’t put it in the fun category. The only time we have welded was on the exhaust piping.

I know they can be a pain....but they need to be fixed. If it was up to me, I wouldn’t want to worry with it. It’s not getting any better setting still.
 

Mr.Gadget

Old Mossy Horns
Not trying to put a hex or anything.
Just want you to know what you could be up.against.
Go slow and use a lot of kroil or other oil.
Welding is what is needed if you break a bolt or stud to get it out.

One think that will help is add oil, get her hot and add more as it cools.
Dont try to break free with cold block, warm it first and try to loosen them some, then you can let it cool and not get a burn taking them out.
That helps some.

Good luck work slow on the bolts.
 

bigten

Twelve Pointer
Contributor
Are you going back with factory style headers? If so, you won't/should'nt have any clearance issues.
As far as gasket style needed, check the pipes at the connection area. Both pieces will be flat if it uses the gasket. If the donut is required, you'll find that the inlet of the converter will be tapered, with the header outlet usually flat. The donut will actually have a flat side to mate to header. If that is the case, be sure to use the grey, high graphite donut that allows for engine movement.
 

Andrewd

Spike
The headers looks like ball and socket type. Most use no gasket. See if header fits the down pipe tight.
 

brownisdown

Twelve Pointer
Contributor
Im no help......this level of effort is where i know my limits and pay the man.

Sent from my SM-G955U using Tapatalk
 

Mechanic Bob

Eight Pointer
I had a 95 GMC 5.7L Z71 and had a small crack in the exhaust manifold. I ended up buying a new crate motor, installing stubby headers and only spent maybe another $1K over repairing the exhaust and having the heads redone.
 

pattersonj11

Old Mossy Horns
This one has had shorty headers for the entire time I have had it and I don’t know how long before then. It has 270,000 on it but it still gets down the road. It has become my yard truck. I live in a dodge for work and this one only sees less than 5,000 miles a year. I use it hunting and around home on the weekends. It’s still a sharp looking truck and I’m attached to it. It was my first one and still the only one. I hate to just letting it go downhill. I need to do some more items to it and am planning those as they come. Going to a new or newer truck isn’t too much of an option. Unless something changes, I would probably hardly get to drive it.
 

Mechanic Bob

Eight Pointer
I had less than $2500 into the new motor and stubby headers. I also sold the old engine for about $500. Bought the crate engine from Jeff Gordon Chevy and changed it in my drive. Had to have my son come down to help me with one bolt on the bell housing that I physically could not get to!
 

pattersonj11

Old Mossy Horns
Part of the reason I haven’t done the exhaust yet was I was debating on a motor swap. Ive looked hard at the LS swaps.
 
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