Down side's to a header?

[Jaredcd7]

My stock exhaust has a huge crack and I've seen that a header for my 1985 720 Rwd Z24 doesn't cost that much more than an exhaust manifold. What if any are the benefits of a header over a manifold? As well the negatives? I finally got her running after my rebuild. I just tonight er on maiden voyage to seat my rings sounds better than expected and quit smoking after about 30 min. Really loud though with the crack.

[datzenmike]

Negatives.

They don't fit. They never fit perfectly.

 

They rust out and look like crap. They only last a few years. Unlike a stock manifold a header needs welding and maintenance to maximize it's life.

 

They increase under hood temperatures.

 

They are not as quiet as a stock manifold.

 

The bolts come loose and gaskets leak. The collector bolts always come loose and needs constant tightening every few months.

 

Little to no increase in power because the stock manifold is more than good enough, unless combined with head porting, more or larger carburetor(s), higher compression and a cam.

 

 

 

Positive

It's lighter than a stock cast manifold

 

[Stoffregen Motorsports]

12 hours ago, datzenmike said:

Negatives.

They don't fit. They never fit perfectly.

 

They rust out and look like crap. They only last a few years. Unlike a stock manifold a header needs welding and maintenance to maximize it's life.

 

They increase under hood temperatures.

 

They are not as quiet as a stock manifold.

 

The bolts come loose and gaskets leak. The collector bolts always come loose and needs constant tightening every few months.

 

Little to no increase in power because the stock manifold is more than good enough, unless combined with head porting, more or larger carburetor(s), higher compression and a cam.

 

 

 

Positive

It's lighter than a stock cast manifold

 

They can be made to fit well, but it usually requires welding.

 

High temp coatings can keep them lasting a long time, like the life of the car/truck.

 

Again, high temp coatings help keep the heat in the tubes.

 

Some like the sound of a header.

 

Proper hardware (like studs in place of bolts) and attention to detail during installation can keep leaks from happening. 3-bolt flanges should be cut off and either a v-band clamp or a thick OEM type flange welded on.

 

Some increase in power. Even just a couple hp increase is not nothing.

 

But yes, if cost is the motivating factor, find a good stock manifold.

[weldingrod]

14 hours ago, Jaredcd7 said:

My stock exhaust has a huge crack and I've seen that a header for my 1985 720 Rwd Z24 doesn't cost that much more than an exhaust manifold. What if any are the benefits of a header over a manifold? As well the negatives? I finally got her running after my rebuild. I just tonight er on maiden voyage to seat my rings sounds better than expected and quit smoking after about 30 min. Really loud though with the crack.

You can always to get a shop to do a welding repair on the original manifold, cheaper than buying either.

[datzenmike]

Get an old one from a wrecking yard that is 'cured'.

[butter fingers]

hey guys and Maddie , over 40 years ago i got my dream truck . a red 1973 620 ! i worked on that truck all the time and modified it alot . i cleaned and polished every part . it took me so many places for work and play , and i always got a compliment . that truck is the reason i have my 86 4x4 today . my 620 had the best headers i could find ,Doug Thorley tri-y headers ! long tubes and supreme construction . the manifold flange was thick and the performance was great . back to the present , my truck manifold was toast and i was lucky enough to  find grandpa's automatic in the bone yard with a fender bender . i wanted the egr tube , but it of course would not come off .they gave me a perfect exhaust manifold with the egr tube at the same price !! this year i installed both and love the stock manifold . still miss my red truck but my 720 is soo much better ! merry xmas everone , Butter Fingers /Grinch