7.4 Vortec k2500 Exhaust Manifold/ Header Install

Couldn’t find the PB blaster but I had some of the WD rust penetrant and just soaked all bolts and studs. This looks pretty tough even with the body lift. I am def worried about broken or stripped bolts in the un-install phase.

It appears non of the smog pumps are close on my truck- just the tubes and connectors. That big one on driver side rear looks like no fun at all!

Dontworry to much. Most likely a stud or two will just come out with the nuts on . The tuff ones will be the flange bolts at the exhaust pipes. Just keep oiling them and use the heat. You get it hot enough it will come out. For the egr tube try to get the top nut first. It's way easier to get to.. Hard to get some ass on that bottom one. Then,if you have to it can just come off with the manifold.. If you don't want to scuff the surface of those headers use some stainless washers before the lock washers. that way they can dig into those. Should look good with those headers..

Yup, have fun drilling the broken ones. I had 2 when I pulled mine off. Plan on all new hardware, minimum a few studs. I put two on each end to get stared, far easier than trying to line up the first bolt- and then just drop the gasket in place with the two outer studs holding it up loose with a couple nuts. Then a stud for the oil dipstick and I think one for the A/C bracket. Antisieze everything.

Thanks all for the input and vote of confidence. I’m going to soak for a few days and strategically map gas on and off before I roll up my sleeves and commit.

Any reason to try to remove hardware after a heat cycle/ drive?

good call on stainless washers- I’ll go to hardware store and grab one per bolt.

Perhaps a moderator will move this thread to the Exhaust sub-forum.

Aparke4 said:

3. Anti-seize: where should I apply? To new studs/ bolts?

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All exhaust fastener threads, and under the nuts/bolt heads.

Aparke4 said:

I do have a MAP gas torch if heat is needed

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Aparke4 said:

I’m going to soak for a few days and strategically map gas on and off

Click to expand...

No such thing as "MAP" gas.

A dozen years ago, MAPP gas was discontinued. It was hotter than propane. Worked nice for soldering copper tubes. To replace MAPP, they're now using fraudulent, deceptive advertising to sell "MAP-Pro", which is useless. Not much hotter than propane, and propane without extra oxygen is good for burning deposits off of spark plugs, lighting bonfires, and not much else.

You're working on exhaust items. You need additional oxygen. I've heard Oxy-Propane works OK, but I've never used it. I use Oxy-Acetylene, which kicks ass. Beyond flame heat, I've used a MIG welder to weld nuts onto broken bolts, which works pretty fair.

If you just go in expecting every stud to snap, and every bolt to break...you'll finish the job faster than you expected.

My '97 K2500 7.4L has at least two broken exhaust manifold studs, and I haven't even tried to remove the manifolds. The studs popped on their own.

How are you planning to attach the sheet-metal spark-plug heat shields? Will they even fit?

Schurkey said:

Perhaps a moderator will move this thread to the Exhaust sub-forum.


All exhaust fastener threads, and under the nuts/bolt heads.



No such thing as "MAP" gas.

A dozen years ago, MAPP gas was discontinued. It was hotter than propane. Worked nice for soldering copper tubes. To replace MAPP, they're now using fraudulent, deceptive advertising to sell "MAP-Pro", which is useless. Not much hotter than propane, and propane without extra oxygen is good for burning deposits off of spark plugs, lighting bonfires, and not much else.

You're working on exhaust items. You need additional oxygen. I've heard Oxy-Propane works OK, but I've never used it. I use Oxy-Acetylene, which kicks ass. Beyond flame heat, I've used a MIG welder to weld nuts onto broken bolts, which works pretty fair.

If you just go in expecting every stud to snap, and every bolt to break...you'll finish the job faster than you expected.

My '97 K2500 7.4L has at least two broken exhaust manifold studs, and I haven't even tried to remove the manifolds. The studs popped on their own.

How are you planning to attach the sheet-metal spark-plug heat shields? Will they even fit?

Click to expand...

Thanks for the input- the "MAP" gas I have comes in the yellow bottle via home depot and was just hot enough to free the pitman arm and idler arm/ centerlink doing some steering parts last year. Hopefully it will provide enouigh heat vs. an oxy torch! If I have to use Oxy-acy I might as well cut it off! That is a nice thing about the new headers is I do not need to reuse the downpipes so I can go ahead and cut if I so desire.

Part of me is tempted to go ahead a book an appointment at a exhaust shop to start the job as I do not have a welder (great tip BTW) and I need to have the Y pipe modifed anyways to clear driveshaft with 6 inch RC lift.

Metal heat shield I was going to throw away as the headers are ceramic coated and I upgraded to the accel extreme 9000 ceramic wires with the ceramic plug boots. Should be OK as instructions for the JBA headers do not specify saving metal shields.

Heading outside now to spray down with PB Blaster a second night...

Yes, MAPP and MAP-Pro came in yellow bottles. MAPP hasn't been made since 2008.

Send me the metal spark-plug heat-shields if you're not going to use 'em. I'll pay shipping. Send me a PM with the price.

I have heat shields in my metal box to the scrapyard guy free + shipping (some have studs rusted on though) as well if he doesn't offer.

I run the Summit plug shields now and moroso wire separators. Yeah yeah Iknow, I have loom to fix that green temp wire, and need to run that #7 the other way, just haven't got to it...

Most of my shields rusted off. When I do wires next, I tentatively plan on using the newer style that's used on the LS and 8.1L.

If I end up not using them I will send em to you no prob!

I am not sure if they will work with the new headers as the tubes are diff than stock design. Looks like mine are in usable shape.

Another night, another soak!

Is it worth pre-heating with Map gas/ yellow bottle? Also what about driving and getting heat on hardware then trying to remove?