Header poll

[Astrodokk]

Since my driver's side exhaust manifold is cracked, I will be replacing with something. I have a blank slate. I know many of you have already replaced yours with different brands and designs, including the pipes as well. Since you are experienced veterans now, I ask:

Would you have done it differently? Are any of you NOT happy with your application? Why?

I've read about several brands of headers, so I know many of you have:

stock
factory headers (newer non cracking)
Banks
Gibson
Hedman
Thorley
other lesser name brands

I have dual exhaust with pipes coming out behind rear wheels. These pipes are rusty with tiny holes in them that I will be replacing and actually having both come out at street side in front of rear wheels. Any of these will work depending on funds. So, my desire in this post is to know if any of these were a mistake for someone or if they regretted going with one brand and wished they had gone with another. Thanks.

On Edit: By the way, I was told by the guys who did my Edelbrock that they recommend Thorley stainless steel. They heard that Hedman ceramic tends to peel or crack off with heat due to thermal expansion and contraction from 2 different types of metal. I know though that Hedman makes different types or styles too. Most of these are California smog legal.

[PeterH-350LE]

When I first got my MH, I had to replace the mufflers and the tail pipes (they were in bad shape). A few month later the drivers side manifold started leaking. I replaced it with a stock OEM GM manifold. Another two month later the passenger side started leaking and upon inspection was warped badly. So I replaced it with the OEM as well.
If I would have known what was to unfold, I would have gone with the banks system.

[ALANSD]

I have heard many good things from users of Thorley headers. on their 454 chevys.
I also crave the Banks system, but it is quite pricey.

[zduke4x]

I have a Banks system that is a vast improvement with stainless headers and 3" tailpipes with heatshields and a lifetime warranty.

I have also read here on the forum that Banks recommends Gibson(also stainless and 3") if they aren't able to fit your rig.

[dinoburb]

Hi Astrodokk,

There are many systems out there that are designed to 'improve' the breathing of the BB chevy. Doug Thorley makes headers designed to improve the torque of the BB Chevy and that is what we towing fools need, more torque.

I have Thorley headers on my 454. They are chrome plated not stainless; recently Thorley, I believe, has released their headers with a ceramic coating (probably the best of both worlds). The Thorley route is probably the most cost effective for improved torque and improved gas milage (some, not much).

Once the headers are on you must plan the exaust system out to the atmosphere. Dual 2.5" pipes with a crossover would probably be the best. Choice of muffler is up to you. Quiet is good for me.

Have you done anything to the other end of the power equation i.e. any intake improvements? The addition of headers, regardless of type (other than stock replacement), causes a change in the gas flow. If there is not a similar change to the intake side of the engine, far less than the full benefit of the headers will be realized.

Just food for thought!

[Astrodokk]

Yes, I just had an Edelbrock Quadrajet 1906 spread bore electric choke replace the old Rochester so that it could pass smog in CA.

What is BB?

[RichardT]

[i]

What is BB? [/B]

BB = BIG Block

[dinoburb]

Sorry,

As you might know Jargon is simply a way for those in the know to keep out those which are less fortunate!!!

BB means Big Block Chevrolet (454 et al)

By the way did you change the intake manifold or are you using the original cast iron manifold? The carb you mention is the stock Q'jet replacement carb, a good choice, but not an improvement in terms of air/fuel flow. An aluminum dual plane Edelbrock Performer manifold might just be the ticket to pull it all together.

Take care,

[Astrodokk]

It's the original. They didn't even give me the option of changing out the intake manifold when they replaced the carb.

Would the intake manifold you mention work with the new carb? Also, does it help with gas mileage?

[dinoburb]

Yes, the Performer manifold for the 454 with the original Spreadbore Q'jet and the Thorley Headers would make an improvement in the milage. The manifold can be purchased for engines equiped with Exaust Gas Recirculation (EGR) or without. Emissions legal to boot!

However, remember this is a 454 which at 11.5mpg is doing outstanding. You can't expect 15mpg from this rig, but you can expect it to run quite a long time if properly cared for.

[74Argosy24MH]

Before you change manifolds check clearance to the doghouse. I put a Holley dual plane manifold and Holley TBI on and had to raise the cover 2".

John

[dinoburb]

One of the reasons I suggested the Performer manifold is that it is a low rise manifold similar to the original cast iron one from Chevrolet. The flow characteristics are better though!

It never hurts to check heights before commiting to any major engine change. Do not use the Performer RPM as that is a high rise dual plane which probably would not clear.

[Astrodokk]

Well, due to limited funds, I decided to go with Thorleys, which are $370. at Summit. The intake manifold will have to wait too, unfortunately.

I've been advised to get the pipes crossed over, but will that work if i have both tips coming out the street side front of rear wheels? I know Peter has his exiting that way...are they crossover?

[thenewkid64]

A crossover is normally installed just rear of the engine to help balance the flow. The routing of the final exit to the roadside will not be effected by the crossover. Before you buy the crossover I would talk to the shop that is doing the install. They may be able to do it for you for less.

[drboyd]

If you do go with the headers, you may want to look into rejetting the carb; headers flow more air and I've heard they tend to make the engine run a little leaner....

-Don