'81 K30 4X4, 454 Exhaust Manifolds....time for headers ?

[Nodakr68]

So upon a recent inspection, I discovered that my driver side exhaust manifold has developed 2 seperate cracks.....nearly half way around on both !!

So I got to thinkin, if I'm gonna have to remove one or both exhaust manifolds, maybe now is the good time to play with headers.....after all, the exhaust is in need of attention anyways. With a stock motor, are headers worth it ? Other than they sound cool !!

I mean cost wise, they aren't much more than a pair of used stock manifolds. What else does a guy mess with ? Timing, jetting, etc ?

 

[bucket]

Some people will say that long tube headers have no business on a stock truck engine. But the fact is, they do add power and not just in the higher rpm range.

With that said, are your cracked manifolds causing any noise? Because they don't always.

 

[Nodakr68]

Some people will say that long tube headers have no business on a stock truck engine. But the fact is, they do add power and not just in the higher rpm range.

With that said, are your cracked manifolds causing any noise? Because they don't always.

Ya know, after 30 years in the power plant industry, my hearing ain't what it used to be.....so I would say no, I don't hear them.....but there is obvious visual evidence of blow-by.

 

[ali_c20]

If you want headers you have to pay $$.
Cheap headers often leak, are made with flimsy walled pipes, rust quickly and sound like a fart in soda can.
Good headers or stick with manifolds, that's my 0.02$

 

[Nodakr68]

If you want headers you have to pay $$.
Cheap headers often leak, are made with flimsy walled pipes, rust quickly and sound like a fart in soda can.
Good headers or stick with manifolds, that's my 0.02$

There so many used ones on the market, makes me wonder why so many people have them and are selling them....Hooker, FlowTech's etc.....Facebook Marketplace is just one spot loaded with used ones for sale...so which are junk and which aren't ?

 

[Old Guy Bill]

The Hooker replacement manifolds are the best option in my opinion.

 

[bucket]

My buddy bought the cheap, Summit branded, coated big block headers for his 1-ton truck a few years ago. I was very impressed with the fitment and so far, they are holding up just as well as any Hooker or Hedman header I've ever owned.

 

[69project]

A set of long tube headers should give you anywhere between 15-30 hp bump from stock manifolds. I had an 86 C20 Burb once with a 454 and I put some Hooker Headers along with an Edelbrock Carb/Intake. It really woke it up since it was a stock engine. You noticed the extra low-end power plus it sounded great. What you are looking for, are headers that have equal, or as close as possible, length runners. That builds the most torque, which makes for more fun on the street. It's been my experience that Hooker builds a quality header for old iron like square bodies, but you have many brands to choose from. You want to look at the diameter of the exhaust runner and collector size. I prefer Hooker over any other brand but that's preference as there are several quality brands out there and it seems some traditional header manufacturers may not be making anything for square-bodies anymore. Any long tube header will be much better than stock as long as you match the exhaust runner and collector size to your application. You don't need a sewer pipe for a relatively stock motor, just something bigger than stock. A short or mid length header will not give you that much benefit and is probably not worth the hassle/cost unless it bolts directly to your existing exhaust. If you have to worry about emissions testing, then headers are not for you.

 

[Zelph]

The Hooker replacement manifolds are the best option in my opinion.

I don’t think they have a big block option for those.

 

[Nodakr68]

A set of long tube headers should give you anywhere between 15-30 hp bump from stock manifolds. I had an 86 C20 Burb once with a 454 and I put some Hooker Headers along with an Edelbrock Carb/Intake. It really woke it up since it was a stock engine. You noticed the extra low-end power plus it sounded great. What you are looking for, are headers that have equal, or as close as possible, length runners. That builds the most torque, which makes for more fun on the street. It's been my experience that Hooker builds a quality header for old iron like square bodies, but you have many brands to choose from. You want to look at the diameter of the exhaust runner and collector size. I prefer Hooker over any other brand but that's preference as there are several quality brands out there and it seems some traditional header manufacturers may not be making anything for square-bodies anymore. Any long tube header will be much better than stock as long as you match the exhaust runner and collector size to your application. You don't need a sewer pipe for a relatively stock motor, just something bigger than stock. A short or mid length header will not give you that much benefit and is probably not worth the hassle/cost unless it bolts directly to your existing exhaust. If you have to worry about emissions testing, then headers are not for you.

So do any timing adjustments need to be done ? How many carb jetting sizes do I need to bump up ? Anything else I may be forgetting ?

 

[ali_c20]

There so many used ones on the market, makes me wonder why so many people have them and are selling them....Hooker, FlowTech's etc.....Facebook Marketplace is just one spot loaded with used ones for sale...so which are junk and which aren't ?

You don't know what the owner did do that headers an why he's selling it, could be warped, leaking or have other issues.
Be careful when you decide to get used headers.
Hookers, Dougs, Sanderson, Patriot are good brands afaik but there are many more.
Also depends on the product line.

 

[ali_c20]

So do any timing adjustments need to be done ? How many carb jetting sizes do I need to bump up ? Anything else I may be forgetting ?

Before touching the carb adjust your timing to what the engine needs. When timing is set you can start to make adjustments on the carb.
Use an afr gauge to tune your carb. As you are building a new exhaust weld in afr sensor bungs on both sides and get an afr gauge.
Search the forum for ignition and carb tuning, lots of knowledge here.

 

[68post]

We used headers on our work trucks for years for the torque increase and mileage benefit. All used mandrel bent 2-1/2" aluminized pipe exhaust, H-pipes, and large case dynomax mufflers.
A stock engine drives better with this , but please tune the ignition and carb, the results are great!

 

[Trucksareforwork]

Only trucks I’m putting headers on these days are ones I plan to sell. I think I have arrived at the “you’re too old” phase of loudness tolerance.

That said I have driven thousands of miles on a set of summit stainless headers and they look fantastic and haven’t been a leakage problem.

 

[Fitz]

I have used, and currently use Hedman 69110 headers on my '78 K-10 BBC. These are for manual or automatic transmission equipped trucks.