1986 454 Headers

Started by zMadMechanic, June 01, 2024, 02:53 PM

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zMadMechanic

Question for you folks - what is my best option for replacement headers? Short? Long?

Mine are cracked and leaking badly (smells in the cabin with engine running).

1986 Chieftain 27 with a smogged 454. I'm not opposed to removing the smog stuff...

Thanks for any input!




Eyez Open

Long tube will work best, improved flow of both gases and heat.

RockwoodMike

Quote from: Eyez Open on June 01, 2024, 03:24 PMLong tube will work best, improved flow of both gases and heat.

Totally agree..If you have the original cast iron ex manifolds, you will really like the difference when the install is complete..dual exhaust system helps too..In other words, don't have all the exhaust feeding into a single output..And make the exhaust as short as possible..Out the sides in front of the rear tires work well..

When you have a long tube going all the way back to the rear of the coach..The engine has to push all that exhaust the full distance..loosing power to the engine..When the exhaust is shorter, the engine needs less effort to get rid of the exhaust..MORE POWER!!..Cooler running too
The best mechanic is the one that can make it run with the least amount of parts!

zMadMechanic

Thoughts on these? think they would hang too low?

https://www.ebay.com/itm/224298679096

RockwoodMike

You are on your own for that question..

I am having some problems on my header install..The problem wit a set of headers is they are designed to fit trucks and cars..Without any attempt to show anything in regards to fitting a Motorhome..

I am in the middle of working my headers for my 73 D22 with a 440..Completely different frame and engine from you..

And I am having some fitment issues..A couple of notches to be cut in the frame..But the problem that might stop all of this is the collector dumps right at the leaf spring shackle..

As for hanging down too low, here is a picture of mine..It hangs below the frame, but I don't think that will be a problem..

The left side always seems to be the problem side and I didn't think there would be a problem..Most of the time it is the steering gearbox that gives issues because it is located on the inside of the frame..

But my steering is mounted on the outside of the frame..

Like I said, headers are designed for trucks and cars with no thoughts for motorhomes..

Soooo..that is my story!!
The best mechanic is the one that can make it run with the least amount of parts!

Eyez Open

Due to the ever present fitment issues with headers i would stick with summit racing as a vendor and support site. Ebay is does not have the depth that Summit has.

Is your RV sitting on a p32 GM chassis?

Now the above is strictly a opinion.

zMadMechanic

Thank you both for the feedback! For the cost, I can't justify Summit racing (all options $750+).

The $250 eBay headers arrive Saturday. I will report back on my progreess!

RockwoodMike

Quote from: zMadMechanic on June 04, 2024, 06:00 PMI will report back on my progreess

If you can, please show some pictures.. :)ThmbUp
The best mechanic is the one that can make it run with the least amount of parts!

RockwoodMike


Here is a preview of what you might be up against
The best mechanic is the one that can make it run with the least amount of parts!

zMadMechanic

Made some progress. Loosened 7 of the 8 manifold bolts on drivers side. The last one requires removing the brake master cylinder, which I was trying to avoid, but probably best to replace anyways based on appearance.

https://imgur.com/a/WpKbhKD

Video is from before I got 3 more loose today. The problem child is the one towards the front of the engine, behind the brake master.

RockwoodMike

Quote from: zMadMechanic on June 11, 2024, 10:48 PMThe problem child is the one towards the front of the engine, behind the brake master.

If you get frustrated, just walk away from it for a while..And while you are away, you can think more clearly..
Then you will come up with better ideas to get it apart, besides getting a bigger hammer!!

Plenty of You Tube videos on handling bad bolts and other things..

You are doing Great!! :)clap  :)clap
The best mechanic is the one that can make it run with the least amount of parts!

RockwoodMike

You mentioned in your video, that the engine has 2 smog pumps and all that tubing that you cut away..

Will you be eliminating that equipment??

Here in Taxifornia, you would not pass the bi annual smog inspection..thus not getting a registration to drive it
The best mechanic is the one that can make it run with the least amount of parts!

Eyez Open

Oh boy I have the same setup, the valley of death comes to mind. My own approach will be...having a fire suppression systems close, clean engine&bay, one hot torch and some instant freeze spray.

Made simple quick heat and sudden freeze, shock therapy. Lol and gentle hand on the strong arm bar..or maybe a light setting on the impact wrench..slowly walking the bolt in and out.q

zMadMechanic

RE: smog deletion/EPA concerns - I have no comment  :angel: but I will say my state does not do emissions testing on older vehicles  ;)

RE: the heat and freeze method - that's interesting! I'll have to buy a can of the freeze stuff for the passenger side.

As of today I'm working on removing the brake master cylinder to access the last manifold bolt. Got 1 of 2 mounting bolts free, and both brake lines free (miracuously), leaving only 2 other mounting bolts for the support bracket and 1 more for the master itself. I'm letting them soak with penetrant overnight before making a final push.

With an ounce of luck, tomorrow I'll get the drivers manifold out...

Eyez Open

Yes it works quite well, but keep in mind there are two points of locked/frozen points in a stud. One being the outer manifold point and the stud in the block.

Shocking the stud loose may take a few attempts, and walking the stud out of block can be slow and tedious. Walking means loosening it a tad then tighten it back up. Some times it easy peasy and sometimes...it's mind bending.

zMadMechanic

Got the drivers manifold off without breaking any of the bolts!  :)clap

For the first time in my 28 years (lol), an extractor socket worked to remove one bolt that was rounded off. Annoyingly, it was one of the 7 I had previously loosened. I'm just happy it's out. They were all heavily rusted, only one rounded off, and none snapped - that's a massive win in my book!

Pictures or video coming tomorrow...

RockwoodMike

Good Job!! :)clap  :)clap

In preparation to reinstall, you need to get a bottom tap to clean up the hole threads in the cylinder head ..All sorts of rusty residue in each hole

And take it easy with the tap..You don't want to jam it or break it in one of the holes..

Compressed air to blow them out clean..

When bolts are going back in, some anti seize grease on the threads will have a good result..Especially if and when you need to take the bolts back out for what ever reason..
The best mechanic is the one that can make it run with the least amount of parts!

zMadMechanic

It was certainly a battle but it could've gone much worse: https://imgur.com/gallery/CGJYM0X



RockwoodMike

It is going to be very interesting to see how things go when you install the new headers :P
The best mechanic is the one that can make it run with the least amount of parts!

Eyez Open

Since the job at hand is a GM chassis and mid 80's class it should be a breeze. Basically a 1 ton chassis two wheel drive.

Now with that being said the reality will soon set in. Starter placement and spark plug issues are just part of the drama...BFH is required in most scenarios.