Headers vs. Stock Manifold

[Stallion]

There are two cylinder heads on a V8:

http://www.caspeed.com/images/trac1pic.jpg (shows exhaust port side)

and two exhaust headers:

http://www.caspeed.com/gallery12/images/stahl6-800.jpg

There is one intake port and valve and one exhaust port and valve per cylinder on a Chevy V8

You can read this page to get a better idea of what the guts of an engine are like:

http://www.caspeed.com/gallery8/index2.html

CYa!
Mako

Okay! I see now. I was confusing heads with actual intake valve openings. I figured that there were separate heads for each cylinder, but I guess that's not the case. So, there's a head on each side of the engine (1 head = 4 cylinders) and then two exaust headers. Okay, I think I understand now! Thanks!

TR

 

[Stallion]

Okay, Mako, I was looking at this picture and I was just wondering a couple of things. You said that the two shiny (aluminum?) parts are the exaust headers. And, on the first picture, those four "holes" are the exaust ports for each cylinder, right?

So, then back on this picture, where are the intake heads here? The rusty part? Or are they not shown here?

About terminology, "headers" are always exaust. But, when people refer to "heads", they mean intake and exaust? Or the only exaust manifold are the headers?

Thanks for bearing with me!

TR

 

[Bob Chadwick]

The intake ports are on the opposite side of the exhaust ports on this head. http://www.caspeed.com/images/trac1pic.jpg

The intake manifold sits in the valley between the two heads with the carb on the top. When the intake valve opens, the down stroke of the piston draws air/fuel into the piston/head chamber. The intake valve closes and on the upstroke the gas mixture is compressed. The spark ignites the gas forcing the piston down. The exhaust valve then opens and on the upstroke exhaust is forced out of the piston through the now open exhaust valve. The exhaust valve closes and the intake valve opens and the process starts all over again.

The same process goes on in all 8 pistons in a coordinated effort.

Bob

 

[Stallion]

When you say opposite, you mean the opposite side of the whole eninge? So, then you really can't see the intake from this picture?

 

[Mako]

When you say opposite, you mean the opposite side of the whole eninge? So, then you really can't see the intake from this picture?

Rather than type up a massive tome on engine-ology:

http://www.howstuffworks.com/category.htm?cat=sc-engi

Please spend a few minutes reading about car engines and drop us a line here with follow up questions.

Tnx!
Mako

 

[Stallion]

I was looking at the car engine and how it works, and it shows that the head just surrounds the intake port. So, how are there only 2 heads per V8? I don't see that if one head has to surround one intake port.

So, it looks like there aren't heads for exaust, just headers as the manifold. Correct?

Thanks!

TR

 

[Paranoid]

These are Big Block heads. They bolt to the block, atop the cylinders, the intake attaches to the top and the exhaust manifolds or headers attach to the openings at the bottom in this pic.

 

[Stallion]

These are Big Block heads. They bolt to the block, atop the cylinders, the intake attaches to the top and the exhaust manifolds or headers attach to the openings at the bottom in this pic.

That whole thing is the head! Wow! Not the mental image I previously had of it, but I'm glad I now know. Just to visually clarify that I know things, attached is the image of the head with a little drawing on it.

If I'm correct, in red are the exaust ports where the headers attach to. In green are the valve springs and lifters?

Thanks a lot! I think I understand (hopefully).

TR

 

[Paranoid]

Yes, except the green circles aren't the lifter, but just the valve springs.

The lifters are in the lifter valley---here's a picture of the lifter valley on a small block(350ci)

You can see the pistons in the lower portion of the pic. This is where the heads attach.

In the lifter valley you can see 16 circles(running the length of the valley) 4pr on each side of the block. The lifters reside in those holes.

 

[Stallion]

Okay, in red I marked with I think you are referring to by the lifter holes, and if I'm wrong, please correct me. Thanks again!

TR

 

[Mako]

Okay, in red I marked with I think you are referring to by the lifter holes, and if I'm wrong, please correct me. Thanks again!

TR

Ya, that's them. The lifters fit in those holes and ride on the cam lobes. See the Solid vs. Hydraulic lifters link on my http://www.caspeed.com/ web page for more info on them.

CYa!
Allen

 

[Stallion]

Thanks a lot for all the help! I appreciate it.

TR

 

[Stingray74CC]

That's why this forum is so great

Someone like stallion, hell me too, can ask all these questions and not get crapped on by the rest of the community members. Thanks everyone for speaking up and giving a little anatomy on the heartbeat of chevrolet.

By the way, I got the two Flowmaster 40 Series welded up today. I asked for the 50 Series...didn't fit. They did a way better job than was done previously and the car sounds amazing. I'll have to get a wav file up as soon as I can.

Has anyone heard of double gaskets b/w the headers and heads. I have a small exhaust leak between cylinders 1 and 3. They guy told me that I could layer Permatex/Gasket/Permates/Gasket/Permatex and it should take car of it. Any tips from the masses?

 

[Mako]

Re: That's why this forum is so great

Someone like stallion, hell me too, can ask all these questions and not get crapped on by the rest of the community members. Thanks everyone for speaking up and giving a little anatomy on the heartbeat of chevrolet.

By the way, I got the two Flowmaster 40 Series welded up today. I asked for the 50 Series...didn't fit. They did a way better job than was done previously and the car sounds amazing. I'll have to get a wav file up as soon as I can.

Has anyone heard of double gaskets b/w the headers and heads. I have a small exhaust leak between cylinders 1 and 3. They guy told me that I could layer Permatex/Gasket/Permates/Gasket/Permatex and it should take car of it. Any tips from the masses?

Everyone has gotta start from scratch... The good news that How Stuff Works site is killer for exactly this kind of basic info. Saves me tons of typing

Yes, doubling up header gaskets is an effective way to handle clearance problems and maybe exhaust leaks. I'm having exceptionally good results using Earl's Pressure Master header gaskets, Summit sells them.

Not cheap but they are working better than any other header gasket I've used so far.

CYa!
Mako

 

[Stallion]

Re: That's why this forum is so great

Someone like stallion, hell me too, can ask all these questions and not get crapped on by the rest of the community members. Thanks everyone for speaking up and giving a little anatomy on the heartbeat of chevrolet.

Truer words were never spoken. He's right. This place is the best and the greatest. Thanks, everyone!

TR

 

[intex99]

This headers thing seems to grab alot of attention so figured I'd ask my question as well.
I got my 80 with headers but they were pretty well shot and my (ex) mechanic told me I should go back with the manifolds because of the heat ect..I did that and as car had nothing else had a local muffler shop custom build me a complete exhaust system.
Well after reading all this about the headers might just go back to them but wondering if after they are installed should I have the engine retuned or does the new headers not affect it with the differnce in back pressure ect.??
I've also played with the idea of sidepipes but could always add them on later on.Anyone have any suggestions on who has a good set for an 80 with a 350??
Thanks all,
Tim:duh

 

[cdhorn]

HI all:

I'm curious about what type of exhaust manifolds were "standard" on the 81. Mine has headers that look factory. Did they come from the factory that way, were they added, or was there an option?

Thanks

Clark

 

[Jack]

HI all:

I'm curious about what type of exhaust manifolds were "standard" on the 81. Mine has headers that look factory. Did they come from the factory that way, were they added, or was there an option?

Thanks

Clark

Clark:
Pretty sure the 81 came standard w/ short headers made of welded-bent tubing. I'd like to see some others chime in to confirm/further explain.
JACK:grinsanta

 

[Jack]

Re: That's why this forum is so great

Has anyone heard of double gaskets b/w the headers and heads. I have a small exhaust leak between cylinders 1 and 3. They guy told me that I could layer Permatex/Gasket/Permates/Gasket/Permatex and it should take car of it. Any tips from the masses?

Tony:
Many headers have a single flange/plate that runs across all 4 ports (connecting tubes # 1 to #3 AND #5 to #7). Dunno if yours are like that? If so, I've seen where some guys will hacksaw through the flange ... effectively separating #1 & #3 ... allowing the tubes to relax a bit and stretch independantly.
JACK:grinsanta

 

[UKPaul]

The '81 came with factory shorty "headers". They are lightweight & supposedly flow well. Having looked in mine, I'm not so sure! There's a lot of weld in them & a very short distance out from the head there is a sharp bend. Additionally, the AIR pipes/tubes cause a small restriction. I'm thinking of replacing mine with some Dynomax Headers but need to know if any other '81 owners have fitted Headers. I want to keep the O2 sensor so will have to fit it in the collector, but will it be hot enough in that position? Will I need a heated O2 sensor?
Paul