1990 454 exhaust manifold replacement

[Erik the Awful]

Nope. The exhaust bolts (you have studs?) slide through the manifolds into the cylinder heads. Typically the exhaust manifolds are warped from the heat and require a manifold spreader for re-installation. As much as I prefer manifolds to headers, you're replacing junk with junk.

 

[ProFarm]

Nope. The exhaust bolts (you have studs?) slide through the manifolds into the cylinder heads. Typically the exhaust manifolds are warped from the heat and require a manifold spreader for re-installation. As much as I prefer manifolds to headers, you're replacing junk with junk.

I agree the factory manifolds are junk but i want to stay as factory as i can get without spending a bunch of money. I am referring to the flange where the exhaust pipe connects to the collector flange at the bottom of the manifold.

 

[Supercharged111]

Weld a nut to what's left and spin them right out.

 

[Schurkey]

Weld a nut to what's left and spin them right out.

Would probably work. I would want that stud glowing orange all the way down to the iron of the manifold first, then let it cool, THEN try to screw it out.

 

[Armalite15]

Yeah you don’t need to replace your manifolds for that. We have a local exhaust guy that basically makes a living drilling out broken and retapping broken studs it’s easy with the right tools. I’d take it off and take it to a competent shop and keep your factory manifolds.

 

[Armalite15]

If you do try welding a nut on I would heat the studs as stated about cherry red and then spray it down with PB Blaster and see if it will back out.

 

[ProFarm]

yep i think welding the nut on the stud is the way i am going to go...I will post pics when and if i get them out.

 

[Schurkey]

Just remember--you want the stud (where it goes into the iron of the manifold) hottr'n ****. Glowing. Then LET IT COOL before backing it out.

 

[Zseventy-one]

there is no way (with the tools and know how i have) I can remove the remainder of the flange studs from the flange holes. I assume they are threaded...

I feel your pain...i tried for weeks to get my flange studs out with heat, pb blaster, stud/bolt extractors and failed miserably. Tried a couple local shops, one said no, the other said no basically through price ($100/bolt) 6bolts =$600.
Took the $600 and got ceramic coated jba shortys with fancy copper manifold gaskets from Mr gasket & installed myself in driveway. Turned out awesome and wallet eventually recovered.

 

[ihop]

I need to replace my exhaust manifolds on my 1900 454ss. I am looking at the doorman manifolds at summit. They come with gaskets, but are gaskets necessary since they didnt use them from the factory? TIA

Yes they are needed. Do not install them without the gaskets, you will not be happy with the outcome.