Headers do or do not help with power and or milaege!!??

[MTtruck]

I'm getting mixed info on this and would like if someone who has a lot of knowledge of Chev 350 could sway me one way or the other. thanks

[69GMCLonghorn]

Headers DO help your mileage and power. If they didn't, high performance vehicles would run manifolds. I have a know-it-all cousin who says manifolds give better low end torque. Don't believe it! If you install headers and get LESS performance/mileage, you need to tune your vehicle and/or check for other problems. Plus, they make a V-8 sound like a V-8 should sound!

[MTtruck]

Thanks so much for the info 69GMClonghorn. gonna have them on Friday night..

[turp mcspray]

I have to agree. The FIRST step to better performance, be it mileage or power is to free up the exhaust. If you look up "exhaust manifold" in the dictionary it says "used to choke your engine" LOL!

[MTtruck]

HA HA!!!!...Yeah dont wanna choke the engine!

[ll____b0t____ll]

I agree with what the others have said and would only add to that a little.
Just like almost any performance adding part you can maximize the power adding affects.
For example: Headers going off into to large of exhaust will net you a little more H/P but cost you T/Q which means you lose some gas milage.

Adding Headers and creating a good exhaust also gets hampered by if you have a restrictive intake manifold and or air filter.

As with most engine parts you bolt on to make "More Power" sorry tool man.. some people fail to see its not about what part you have rather what combination of parts you have.

An Example of this might be:
You bolt on headers and gain just a little.
You bolt on a high flow intake manifold and gain a little.
You bolt on a carb that has a higher rating and gain a little.

Now none of these bolt ons by them self seem to realy make you feel as though your money and time was well spent in some cases but.
The combination of the three net you a larger number in H/P and T/Q because you have carried over from one part to the next with the same technic , increase air flow and with that increase in air flow add gas and better evacuate the spent fuel out less restrictive exhaust.
Now provided you havent over shot your cam with a intake that pulls completly on a different RPM curve than your in line for a good boost.

But as I said I agree a set of headers is a decent first step towards more performance but be warned ... once the more power bug bites you...its real hard to stop looking for more power lol.

P.S. And dont let people fool ya making more Torque is a great way to increase gas milage as it makes your moter feel like its in a lighter vehicle and so the engine doesnt have to work as hard to do what it did before.

[mrein3]

I guess I'll have to be the dissenting vote here.

What I have observed is that most people have no clue what their power and/or mileage is going into a set of headers. They bolt on a crappy pair and say oh wow these are great. Then I get the call to come over and help them try to seal them up after a week of running to the grocery store.

Until I see dyno pulls before and after on the same vehicle or a couple months of gas mileage before and after I'm going to stick to my opinion.

A NASCAR tuned racing engine with headers is one thing but a pair of headers welded together by some China man and bolted on your engine is quite another. A high end racing engine has an engineer designing and/or a good mechanic tuning the total package. The spec sent to China to manufacture what most of us can afford is made to work ok in all applications. I'll take my factory ram's horns specified by an American Engineer for my truck and cast here over an aftermarket works with any application ready to rust out set of headers any day

IF you insist on headers, wrap the crap out of them. You need to keep the heat in so it keeps the velocity in the exhaust to keep the scavenging effect flowing.
ll____b0t____ll and some of the others touched on what I'm saying. You can do better with headers over ram's horns. Most people don't however because they just slap them on there and go. Based on what I've observed that others do with headers I'd save that money for something else.

[turp mcspray]

The factory used manifolds for simplicity and longevity. Do an internet search on the subject. I can't believe you would find anything suggesting manifolds would be better.

[big_al_71]

Headers make a HUGE difference in performance usually gas mileage is horrible with a performance motor at least it is what has being my experience.

[ll____b0t____ll]

I wouldnt wrap the headers at all unless they are high doller coated headers.
Just wrapping say some cheap black coated headers will do nothing but leave you with exhaust leaks as they rust to nothing and fall to peices.
Short term thats ok but who wants to keep fixing the same problem over and over and over and over and...

[mrein3]

Originally Posted by ll____b0t____ll

I wouldnt wrap the headers at all unless they are high doller coated headers.
Just wrapping say some cheap black coated headers will do nothing but leave you with exhaust leaks as they rust to nothing and fall to peices.
Short term thats ok but who wants to keep fixing the same problem over and over and over and over and...

Which is why I'd stick with the stock manifolds. I have heard of a place where one vehicle driver has bolted on a set of headers and never had to mess with them but I've never been there myself.

If it ain't broke...

[69GMCLonghorn]

I didn't do dyno runs, but picked up 1 MPG avg (city and hwy) when I installed the headers with correct exhaust for the motor. If you go too big, you're right, you'll lose torque, etc.

In terms of headers not sealing, it can be a problem, but then I've had friends with problems sealing up manifolds too. I've had my headers for 5 years and tightened the bolts about 3 times. Not too bad. Oh and they're the cheap $79 Summit headers, which are FANTASTIC!!

[turp mcspray]

Header wraps do a good job of keeping the heat in to keep velocity up. The downfall is they get heat fatigue something terrible. I have seen two year old headers unwrapped and nothing left but dust. I wouldn't recomend the wrap on a street car.
As far as leakage, headers of today are much better quality than years ago. I posted awhile back that the headmens on my orange blazer are 10-12 years old and the ONLY time I have ever replaced collector gaskets was when I hit my muffler on a boulder which turned my exhaust at the header and tore the gasket. I have never had to replace the gaskets at the head. My elcamino has summit brand headers on it and I have never replaced the gaskets on it either. And they to are 10 plus years old.
The key is to retighten the bolts every couple of days untill the gaskets stop squishing and take a set. Then when you change oil or do regular mainteance check em. The old wives tale that headers always leak is BS!
When looking to improve your engines performance the exhaust is ALWAYS, ALWAYS the first step. Don't take my word for it..do some research. I'm not trying to stir things up,But years and years of research and hands on experiance have NEVER shown me where manifolds had the upper hand.

[69GMCLonghorn]

I also saw something on the Power Block last weekend that was cool. It was a set of header bolts that had the 3/8" head so you can actually get a wrench on it. That isn't a new idea, but what I had NOT seen before, was that these bolts had an allen head set screw in the middle! Basically, you torque the bolt down as usual, then tighten the set screw. The bottom of the bolt is cut in a T pattern, so it flares out and keeps it tight!

That of course, is only for those believing in previously stated wives' tale... I don't...

[chevy_mike]

I'm going to stay out of the debate of mileage/performance. Too many variables to make a specific call.

As for leaking headers, if you get good one, good gaskets and bolts, it is possible to get ones that don't leak ever.

My '69 Camaro had Thorley headers (thick flanges). I put them on with Earls header gaskets, which are metal with "lead" type compression areas (which were replaceable if needed). I used "pin" locking bolts that you would torque to 15 ft. lbs. and then tighted the set screw pin in the middle that would spread apart the split end of the bolt. Once locked in place, you can't turn them unless you loosen the pin.

After 2 years and about 5,000 miles, they never leaked or loosened up. It wasn't a cheap way to go as between the gaskets and bolts, they costed more then some of you are spending on the headers but it sure made a difference in not having ANY issues, unlike prior experiences.

YMMV

Edit - 69GMCLonghorn is talking about the bolts I used. I just can't recall the name of them but I did get them from Summit Racing.

Edit Again, Here is the bolts on Summit's site,

http://www.summitracing.com/parts/PHP-21003/

[mclairmo]

Get ceramic coated or stainless headers if you want them to last and not rust away. I have run Dynomax coated headers by Walker on my 396 for 15 years and they have never come loose or had any problems at all. Still look like new. They do increase power and mileage if properly and carefully matched to the rest of the engine and exhaust components. It all has to work together as an integrated and well thought out system.

[capev86]

want horspeower, don't haul weight and have cash to burn...get headers.

want to get good all around performance, save money and not fallow the fashion crowd....stick with the ram horns....

headers often fail (rust, break, etc) because they are thin gauge whereas the stock manifolds (that perfectly fit these trucks) are rugged.

i will just blast and hot coat the ram horns in my 72 burb 3/4 ton 2wd when i swap the 307 out for my bad boy 406sbc. gonna spend my money on a stainless magnaflow exhaust from lmc truck that sports an x-pipe. that will give me good flow, retain throttle response and keep something original on my rig!

nice thing about the ram horns is they flow very well for stock manifolds, unlike the ugly things that came on later generation trucks. but to each his own.......

[mclairmo]

If going with ramshorns, try to get the 2.5 inch diameter collector versions from the Corvette. Maybe even port match them to the exhaust ports. I will probably do this for my truck since I want a trouble free, long lasting and quiet exhaust.

[69GMCLonghorn]

Originally Posted by mclairmo

If going with ramshorns, try to get the 2.5 inch diameter collector versions from the Corvette. Maybe even port match them to the exhaust ports. I will probably do this for my truck since I want a trouble free, long lasting and quiet exhaust.

This could go on all day/month/year, and very well may. But I'll keep it going for one more round:

When I bought my truck, it had ram horns, dual 2 1/4" exhaust with LOOONG glass packs, run out to the rear bumper, very quiet... I ripped that out and installed Summit "cheap thin walled", rustable, uncoated, ghetto-a** headers. I ran 2 1/2" duals with Magnaflows and an H pipe all the way out the back as before. Lo and behold the thing was as quiet as with before and actually sounded about 1000 times better.

Now had I not just sold my truck, my plan was to rerun it out the sides with the smaller Magnaflows and let people know for sure that I was taching 2000 RPM on the highway! Guess that'll wait for the next project!

[big mike71]

I got more power but less gas mileage, because I get on it more.

[Skirkpat]

The effective backpressure of a manifold should move your tourque curve lower.

I for one think headers are something that belong on race cars.They come with alot of problems, some of which were disscused here most were missed. One main problem and the real reason for a header wrap is keeping heat headed out the a$$ end, and not back into the intake charge and carb body, not to mention the starter. Hot air is bad for fuel density.

Ultimately it's all about your combo. If you have 2.02 intake valves, high lift roller rockers, high commpresion/high lift cam, Then headers make ALOT of sense. If you have 8.5/1 stocker you are wasting money IMO. I know that there are alot of people that swear that their 85.00 headers are just short of putting a blower on their truck...I have never seen that type of a benifit from a semi-stock/ stock engine in a very heavy vehicle, JMO

[ll____b0t____ll]

Originally Posted by MTtruck

I'm getting mixed info on this and would like if someone who has a lot of knowledge of Chev 350 could sway me one way or the other. thanks

And that looks like what your getting more of "Mixed Info" .sorry for that.
Looks like your going to have to come to your own conclusions as this sight may be helpful most the time but anytime you say a part is good theres some one else to say no it isnt.
Thats the world we live in, some dont know , some do , some troll , some are misinformed , some just like to argue , some honestly think they know , some know they dont know but say anyway just to buffalo you , some are young with no experiance and some are old with no experiance , some are young and know what they are talking about and some times you just get a half drunk old peeved off at the world internet junkie with a brain that tells itself it knows all.

You got people who paid for the part and like it or dont and you got people who because they decided not to buy the part tell others not to because if they dont need it neither do you.

Youll have to deal with this all up through your life most likely so do your best to find the facts and ask for help when you need to but learn to sift through the BS the best you can.

Your talking about a reletively cheap part to find out about so maybe buy them and try them out yourself and then come back and post how much you either love them or hate them.

[mclairmo]

I think I fall into the "half drunk old peeved off at the world internet junkie with a brain that tells itself it knows all" category. What about everyone else? I think ramshorns are prettier, especially when shaved and ground smooth and ceramic coated.

[ll____b0t____ll]

Originally Posted by mclairmo

I think I fall into the "half drunk old peeved off at the world internet junkie with a brain that tells itself it knows all" category. What about everyone else? I think ramshorns are prettier, especially when shaved and ground smooth and ceramic coated.

Well you said it yourself in another thread that you married for looks so looks must be the most important to you but weather or not you think they look better does not speak to weather or not they make more power or get better gas milage which is what this thread is about.