Headers or iron manifolds?

[hclanton93]

Both. The wires have burnt from touching the header even with the protective sheaths on them. A boot burnt from radiant heat.

 

[SUBURBAN5]

I had some pace setter headers a long time ago. Didn't experience that. I mostly went through exhaust leaks that finally pissed me off to get manifolds again. Plus changing number 8 plug sucks bigtime.... now that my manifold is cracked I'm gonna try ceramic coated headers. Well see how it goes....

 

[GrimsterGMC]

I had some pace setter headers a long time ago. Didn't experience that. I mostly went through exhaust leaks that finally pissed me off to get manifolds again. Plus changing number 8 plug sucks bigtime.... now that my manifold is cracked I'm gonna try ceramic coated headers. Well see how it goes....

I have ceramic coated and never had a problem, only when I first installed them and had a wire touch the pipe when a clip failed. Just keep them clipped out of the way and you will be good.

 

[SUBURBAN5]

I have ceramic coated and never had a problem, only when I first installed them and had a wire touch the pipe when a clip failed. Just keep them clipped out of the way and you will be good.

Good to know. I'm ordering ss header bolts/ should I do the same for the flange or just use the provided bolts and washers?

 

[L31MaxExpress]

Wasn't crush bent on earlier 400s not later? My original exhaust on the burb was smooth bends from front to back.

All the ones I have looked at were definitely not crush bent. 99 suburban, 99 Tahoe, the 97 van. They have all been mandrel bent and the ones I have had my eyes on were stainless as well. Stock Express van exhaust, always thought it was kind of goofy to have a resonator ahead of the passenger side cat. The Thorley headers 86'd that resonator. The resonator on one bank reminded me of the old Fords that had a catalytic converter on only one bank. Having those big pipes on the L31 is why I feel shorties made a big difference and ditching that chambered resonator is probably why my L31 loved the Thorley tri-ys.

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[SUBURBAN5]

All the ones I have looked at were definitely not crush bent. 99 suburban, 99 Tahoe, the 97 van. They have all been mandrel bent and they ones I have had my eyes on were stainless as well. Stock Express van exhaust, always thought it was kind of goofy to have a resonator ahead of the passenger side cat. The Thorley headers 86'd that resonator.

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That's what I thought, but I don't exactly crawl underneath to check out every 400 I come across lol.

 

[L31MaxExpress]

That's what I thought, but I don't exactly crawl underneath to check out every 400 I come across lol.

I have owned quite a few and most of them were purchased with mechanical issues. They either got repaired, driven for a while and flipped or parted out in some cases. I also worked on my fair share, working in a shop when these were under 10 year old, untouched trucks.

 

[Supercharged111]

The manifolds fit the G-van chassis with ease. The manifolds are 2.5" exit, GM 2.5" donuts fit them and I used Pypes 2.5" big block head pipes with them. While I was working on test fitting everything. I switched the outlet flanges from the included bolts to studs and nuts and from gaskets to donuts. I ended up picking up two complete sets of L31 heat shields. One for this engine and another set should a pair of these find their way on my 97 in the future.

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Still haven't cleaned that transmission I see.

 

[L31MaxExpress]

Still haven't cleaned that transmission I see.

Same picture you saw before. But nope cleaning it might let the magic out of that Turbski 400.

 

[PlayingWithTBI]

The resonator on one bank reminded me of the old Fords that had a catalytic converter on only one bank.

That's kinda like our '02 Q45, it had 3 cats, 2 mufflers, and 2 resonators

The 1st 2 cats were on the exhaust manifolds so, when the cats went out, you had to replace the manifolds too - up to $700 per! That didn't last very long, when it came time to get an emissions test, I junked the car since by then the PCM bricked.