# Headers & Exhaust



## Abe (Jan 19, 2000)

I am getting ready to replace my exhaust system on my 78 3/4 ton 4x4. It has a 400 pretty much all stock still. I was told that running headers would increase fuel and performance, and that if I was to run headers to run either an H or an X in the exhaust right behind the headers as close as possible. Supposidly this will lead to an additional horsepower, torque and fuel bonus,
anyone know about this or what is recommended or worth my time??

-Abe


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## Harold (Feb 12, 2000)

Abe, I have a 75 3/4 ton I changed into a 4x4 with a lot of mods along the way. I have a set of Doug Thourley headers on mine. They aren't cheap, but the best. They will improve your low end-mid range torque which will effect your mileage and power.
You will need the help of a qualified person to help you choose which header to purchase. Don't get cheep ones. You'll be sorry in the long run.
Putting in the connector between the pipes is kind of splitting hairs, but not that costly. It does help, but in a minor way.
To get the bennifits from what you are doing, you should look into a intake manifold like an Edelbrock performer, and recurve your ignition. Together, these modifications will help to wake up your truck and improve both the power and mileage.
Harold


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## John DiMartino (Jan 22, 2000)

Abe, there are a lot of ponies waiting for you to uncork and the gains are really noticable.I have owned 4 trucks similar to yours,I put headers on the first 3 and left the last one stock.Here is why,leaks,leaks and thin wall collectors from cheap 100 dollar headers.If you do install a set,do yuorself a favor and install a quality set and you will have no troubles.Look for 3/8 flanges,stainless steel,or at least nickel or the ultimate, pro-tec coated stainless steel.Harold knows his headers,Doug Thourly are top of the line.They provide low end response and torque at the cost of high RPM power(most trucks need torque more than RPM's)and will put a smile on your face when you hit it or are towing.They also fit great and the set I put on didnt require me to raise engine like others.Borla also makes great headers,JBA,and Arizona speed &marine.These are not cheap.I have put on Edelbroc TES headers,they are not as well built and will rust out after 3 or 4 years in salt belt,but for the money they are the best bet if you are on a tight budget.They also dont have as thick a flange and will burn out gaskets on occasion.Good luck and dont skimp-just run manifolds rather than a cheap set,you'll save a lot of aggravation. John Dimartino

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John D


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## Abe (Jan 19, 2000)

I was just lookin around and have a question, what is the diff between EGR and Non EGR??

in order to purchase new manifold for my truck, have to know if it is egr or non egr

-abe


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## John DiMartino (Jan 22, 2000)

The egr valve will be on the intake manifold,passengers side between the valve cover and the carb.It has a round steel top about 3-4" in diameter.It will,or is supposed to have a vacuum line hooked to it.The EGR valve is for emissions and helps control pinping at part throttle.It is important to keep all emissions equipment functional,for performance and upcoming smog checks.The tag on the fan shroud or hood (if u can still read it)shows all vacuum lines and emission equipment that the truck is supposed to have.Look on there it will show the egr valve to if it has one.Good luck Abe John D

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John D


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## Abe (Jan 19, 2000)

What are the biggest differences between thorley and hedmans?

-abe


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## Harold (Feb 12, 2000)

abe I have used both brands and cannot say enough good things about Thorley headers. I don't think you could burn out a flange gasket on a Thorley header if you tried to. They are built WAY stronger than any other header I have ever seen. The "try y" truck header is a real good one for low end and mid range torque in a truck. Torque, not horse power is what gets you moving.
I know the Thorley headers are pricey, but the other fellow was right. If you are not going to run the best, you are better off just running stock manifolds. The trouble you will have from cheaper headers is not worth it.
Harold


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## MTCK (Feb 13, 2000)

I haven't tried thorely's yet, but they sound pretty sweet. You deffinetly have to dish out some cash to get a decent pair though. Hedman makes an Elite serries that work well. They go for about $250 out of performance automotive warehouse, and have thick flanges and sturdy primarys. They're coated, and have never given me a problem. But don't go for the cheap hedmans, I had a friend try that...... Not pretty, they went to hell pretty quick.


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## Abe (Jan 19, 2000)

thanks for the input all, I think that I will get the thorleys. I am pricing them out cant believe the price difference between different shops, for my truck they have ranged from $305 to $650, talk about some mark up or something!, by the way I called thorley enterprises, just to ensure i was asking for the right part from everyone I call, I cant believe that some outfits out there are swindling us that badly!

oh well

buyer be ware i guess!

-abe


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## John DiMartino (Jan 22, 2000)

I'm glad your buying a quality set of headers,and 305 bucks is a great price.Think of it this way,the thourley's will out last 4 sets of cheap headers and the labor you saved+ figure 3 sets of gaskets for each cheap set of headers and the aggravation,scraped nuckles Etc..

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John D


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## BULLDOG (Feb 24, 2000)

Thorley's r the bet u can get w/out a doubt!!


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## Captkaos (Jan 3, 2000)

Keep in mind there are 2 Thorleys making headers now. Doug and his ex-wife.
http://www.thorleyheaders.com and 
http://www.dougsheaders.com

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Chris Lucas
http://www.wwisp.com/~captkaos


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## 525 (Feb 27, 2000)

Abe - Back in 94 I had a 1989 Scotsdale with a 5.7 and 3spd auto. My mileage was around 11 - 12 on the highway. I installed Edelbrock tubular exhaust system which utilized all the correct emmisions. The cat was left in place and I finished up the system with the Thrush CVX catback exhaust. My mileage increased to 15 on the highway and it had a nice mellow tone to boot. I installed everything myself and the cost at the time was around $550.00 complete. Hopes this helps.


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