I dont like all the headaches of headers and want manifolds.
If I get them I would take them to a machine shop and have them ported if not way too expensive.
My question are.

1. Is there a manifold that is better then others for my application?
I have double hump heads with 2.02 valves on a 350 block .30 over. I am not sure what cam I have. I might be able to find out if important.

2.Does it matter if I get them used?

3. Are the prefered manifolds hard to find?

What "headaches of headers" are you experiencing? More than likely there are tips and tricks to alleviate those headaches. Headers can definately be set up to be just as "reliable" as manifolds. Really the only reason to stay with manifolds is A) keeping the car stock and B) can't afford to buy headers.

a quality set of headers is the way to go,use good quality gaskets(not paper) and either locking header bolts or loc-tite on the threads and there should be no problems other than going over speed bumps if your car is too low,even then you could get "shorties".

To pass-up installing headers is giving away horsepower for no good reason. Maybe you or people you know have had bad luck with cheapie headers and poor install. Use a quality header with ceramic coating and copper gaskets and you won't have any problems.

I remeber readin in a car craft mag where they did a comparison against headers and ported manifolds? For like a sleeper or his application?

That brings up a question, Tag...
were all small block stock exhaust manifolds the same?
For example, in 1972 models, did the 135hp 307 get the same casting as say a 175hp 350 motor?
Were the down pipe diameters the same size (2") between the two ??
I realize the hi-po motor got duals.

What "headaches of headers" are you experiencing? More than likely there are tips and tricks to alleviate those headaches. Headers can definately be set up to be just as "reliable" as manifolds. Really the only reason to stay with manifolds is A) keeping the car stock and B) can't afford to buy headers.

There's now an excellent 3rd reason to use the "stock" exhaust manifolds. With the advent of the new "F.A.S.T." class racing that started about 2 years ago, "race-cars" in this category are required to use them, along with the original size street tires that came on the car. We're in the middle of "porting" a set now. When we get the shape and contour worked out, they will be shipped to "Extrude-Hone" to be opened up some more. I had posted about this new type of racing and was approached by some customers to build a couple of units. As of today a Vette that ran at Englishtown has the record, I believe it ran like a 10.60 on street tires and is all correct factory appearing. This type of unit will have NO bottom end torque, but all muscle upstairs. We should see some "average" et's, but some above average MPH's. Thanks, Gary in N.Y.
P.S. You have to keep in mind, sometimes headers are only worth add'l power when they're uncorked. We do have a bunch of excellent running units with
"factory" pipes. We've tested many of this type. The 1972 LS-5 we tested recently with both stock exhaust manifolds and headers made no difference in power.

Find a set of manifolds off a 400SBC, pretty sure these used a 2-1/2" head pipe. Even if they have the AIR taps, just remove the tube and plug the hole. HO Vettes got a 2.5" ram horn manifold that flowed real well.

OK, I understand your frustrations here..

Try Sandersons for cast-iron "headers" that flow better than stock!!

http://www.sandersonheaders.com/

I do have to say, they will be "pricey", imho...

pdq67

I have run both headers and exhaust manifolds, the last 15 years has been ported exhaust manifolds with large tubo mufflers on my '64 Malibu big block. They don't leak, they don't come loose, they don't give you that exhaust drone on the highway and the biggie for me is that it's much easier to work on the under side of the car in the motor area with the exhaust manifolds, because the header tubes take up too much room. And on the street with a full exhaust system I don't think there is much preformance benefit. It's just the header noise that makes you think your going faster. With 2.5" pipes, exhuast manifolds and turbo mufflers my car has that factory muscle car sound that I like very much. Dave

Headers increase the performance greatly on a big block, my headers don't come loose, they don't leak and I don't drive it on the street as much as you probably do. But Headers DO increase performance as does 3" exhaust at least.

Do headers really make more power with mufflers?

I tested my chvelle 71. made 245hp stock. (454 bigblock with smallport intake)

Then i exhanged to open air filter and headers and made 291hp.

But i think it was the open air filter that made it.

Went 0-60mph testing in 7.10 before and just changing air filter i made 6.30 runs.

After that i changed to a viktor JR, holley 800 and a magnum 292 and made 397hp.

All powers are RWHP.

With a stock car, stock stall etc i made 12 sec runs without posi on 225 radials, with 3.19 gear wih only headers, cam swap, intake and carb.

I use a quality set of headers on my chevelle and don't have any problems. I have the old vette 2 1/2" rams horn on my 55 and am very pleased with those also.

Actually I like the sound of the rams horn with series 40 flowmaster and full exhaust better than the chevelle with series 60 full exhaust.

One thing to consider is the rams horn manifolds will not fit in your chevelle unless you move the motor back 2 inches.

Of course the log stlye mainfolds are the worse from what little I know.

Yes, headers "allow" you to make more power even with mufflers. How long ago was the above tests? Todays mufflers are VERY good and in many cases a car will be faster with the mufflers than running open. You also have to take weight into the situation. Cast iron manifolds are heavy.

If you are dead set against headers, look into a set of Sanderson "Cast" headers. They are cast like manifolds (except a lot nicer) and they flow like a header. This may be the best thing for what you want to do.

www.sandersonheaders.com or here is a direct link http://www.sandersonheaders.com/pagesbypartnum/qp1200.htm

Those Sandersons look very interesting.

Are the spark plugs able to be changed with them on?

Will they fry spark plug wires like headers?

It looks like the exhaust exits them close to the stock location. So could you hook a stock exhaust system up to it? I dont have one but that would be nice so in the future I do not have to go custom this and that.

Did I read the price guide correctly at $350? I dont think that is a bad price you could spend that on a pair of headers.

At first glance I like them thank for pointing them out!

Please let us know how you turn out so we can see how it works out for you..

Thanks,

pdq67

I dont like all the headaches of headers and want manifolds.
If I get them I would take them to a machine shop and have them ported if not way too expensive.
My question are.
1. Is there a manifold that is better then others for my application?
I have double hump heads with 2.02 valves on a 350 block .30 over. I am not sure what cam I have. I might be able to find out if important.
2.Does it matter if I get them used?
3. Are the prefered manifolds hard to find?
------------------------------------------------------

According to an old HP article, header can increase HP from 10 to 16 HP on a SB. On a BB, it can be 12 to 20 HP, but that all depends on the engine and rpm you going to run.
If you don't plan on going to the track, I can see no reason to add headers. For almost all street applications, dual exhaust and good mufflers will do fine, just as someone has already stated.
If you plan on going to the track more than a few times a year, headers are not a bad idea. You can always use the shortly spark plugs to avoid the burned wires. Or they make small white heat-proof socks, that also work very well.

Well I am set on buying the Sandersons you guys have told me about. Probably when I get my Tax return. So basically in a few weeks. Thanks guys.

Well I am set on buying the Sandersons you guys have told me about. Probably when I get my Tax return. So basically in a few weeks. Thanks guys.

Digging up an old post, but did you get them?

That brings up a question, Tag...
were all small block stock exhaust manifolds the same?
For example, in 1972 models, did the 135hp 307 get the same casting as say a 175hp 350 motor?
Were the down pipe diameters the same size (2") between the two ??
I realize the hi-po motor got duals.
as far as i know ,all of them were the same with the exception of A.I.R. holes or not from like 70 or 71-86 or 87. this was all i could find recently when trying to find some for a swap i did. the only variations were the 7 bolt style of the mid 80's heads and the "log" style ones of the 80's trucks.if your car will permit their design to be used,the 60's style "ram horns" are supposed to be the best flowing factory manifolds. also you may want to look at Sanderson Headers. they make cast style manifolds that flow more like headers,sort of the best of both worlds.