HP exhaust manifold verses Header comparison

[33 IMP]

NOT NOW https://www.ebay.com/itm/Mopar-62-6...666440?hash=item54895a8f88:g:440AAMXQMmJRMW2x

Those are repops of the common (?!) Maxwedge manifolds. The tri-y stage threes have not been reproduced, are extraordinarily rare, and the last pair I heard of for sale, asking price was over 10k. Well over.

 

[RJRENTON]

NOT NOW https://www.ebay.com/itm/Mopar-62-6...666440?hash=item54895a8f88:g:440AAMXQMmJRMW2x

I'm aware of these repro unuts....they have the part number of 440426413-r and -l. They are excellent repros but never personally used them.
BOB RENTON

 

[33 IMP]

I wonder if those repop max manifolds could be turned around, and feed into a couple turbos.
Hmmmmm......

And maybe plumb them into a crossram???

 

[pa moparman]

Verry nice car. Mopar muscle did a test years ago on headers vs mopar hp manifolds and there was not that much differnce plus the heat that headers put out under the hood. I wish I could rember what year it was they did that test, With the way things have changed it may not be the same. I myself dont like headers because of the heat.

 

[origcharger]

Whenever I hear someone say that they have put headers on and it never made much difference, I think they most likely weren't good headers.

 

[Kern Dog]

Verry nice car. Mopar muscle did a test years ago on headers vs mopar hp manifolds and there was not that much differnce plus the heat that headers put out under the hood. I wish I could rember what year it was they did that test, With the way things have changed it may not be the same. I myself dont like headers because of the heat.

False.
Headers run cooler due to being able to dissipate heat far quicker. Point a thermal gun at a manifold and at a header tube.
Headers make power even on a stock engine. As compression, cam and carburetion are stepped up, the gains with headers increase as well. You have been fooled, Sir.

 

[Tim Ziegler]

BIG drag race, 500 competing in all classes, 100 percent have headers

 

[RJRENTON]

BIG drag race, 500 competing in all classes, 100 percent have headers

Please state the basic particulars.....the WHO, WHAT, WHERE WHEN....Difficult to make an exact determination based on undefined quantities. Usually, in life, there is never a 100% chance of anything...
BOB RENTON

 

[Don Frelier]

Headers run cooler due to being able to dissipate heat far quicker. Point a thermal gun at a manifold and at a header tube.

The engine is putting out the same amount of heat and yes the header is dissipating it to the air under the hood. So the surface temperature is lower but underhood temperature will be higher than with manifolds.
This isn't exactly a good thing for efficiency because its easier to move hot air than cold air.
Now on the other hand a manifold has stored thermal energy in it's mass of iron and will remain hot longer after the car is shut off.
But even that amount is fairly small percentage when compared to the block.
I wrapped the headers on my Satellite for these reasons, it was a real pain in the ***.

 

[origcharger]

If you want to find a non contributing cylinder with an infra red thermometer, it is much easier with headers.

 

[Tim Ziegler]

RJ, at a NHRA national drag race, from stock eliminator to top fuel every race car has headers -100 percent. They aren't there to lose

 

[pa moparman]

headers may disapate heat when your sitting with the hood up in your driveway . But take your heat gun and crawl under the hood with it closed running down the road and see what happens. Yes all race cars run headers but they dont run mufflers either.

 

[Don Frelier]

How do you crawl under the hood with it closed going down the road?

 

[Don Frelier]

Not trying to be a dick, it's just not clear what you intended to convey there.

 

[moparedtn]

How do you crawl under the hood with it closed going down the road?

Verrrrrry carefully....

Lookit, headers definitely make things hotter in the car over stock manifolds.
Methinks it's got to do with radiated heat of one versus the other; headers obviously don't have the
cross-sectional density of cast iron, so they release heat much more readily, heating up everything
around them.
Make sense?

 

[Tim Ziegler]

Heat or no heat, HEADERS FLOW. You don't see the racers I mentioned running open exhaust manifolds

 

[Kern Dog]

Verrrrrry carefully....

Lookit, headers definitely make things hotter in the car over stock manifolds.
Methinks it's got to do with radiated heat of one versus the other; headers obviously don't have the
cross-sectional density of cast iron, so they release heat much more readily, heating up everything
around them.
Make sense?

I have never ran manifolds on a big block in a car but My 75 Power Wagon did have them for the first year that I owned it. The heat coming off of the manifolds sure seemed to be more than what comes off of the headers now.
Almost every 318 or 360 I've had in a car had manifolds. I have to disagree with you Ed, I would need to see a thermal test to believe you on this.

 

[66 Sat]

I read this earlier today, makes some sense to me:
Cast iron gives exhaust manifolds sturdiness and longevity. Because the cast iron material is thick, it holds on to heat well, which is good for emissions and keeps heat from leaking to other nearby parts.

The thick walls do, however, mean there is a small space for exhaust gases to pass through, and the iron casting makes the interior rough, which can slow the flow of exhaust gases. This slow flow of gases creates back pressure, which keeps the exhaust from being cleared as efficiently as possible. This reduces the efficiency and ultimately the power of the engine, because exhaust must go out to allow fresh fuel and air in.

 

[BSB67]

This thread has sure gotten funny.

 

[moparedtn]

I have never ran manifolds on a big block in a car but My 75 Power Wagon did have them for the first year that I owned it. The heat coming off of the manifolds sure seemed to be more than what comes off of the headers now.
Almost every 318 or 360 I've had in a car had manifolds. I have to disagree with you Ed, I would need to see a thermal test to believe you on this.

It may be application-specific for me experience-wise, but after having had b-body big block cars that
have had both manifolds and headers (either/or), I can state definitely that the ones with headers had
markedly higher temps radiating into the passenger compartment.
Headers are a bunch larger, of course, and all that big tubing being real close to the firewall and footwells
of the passenger compartment meant radiation of heat.
Manifolds are smaller, more compact - and instead of a collection of pipes heading down to a common
collector under your feet down there, the single exhaust pipes coming off the manifold flanges of manifolds
took up less space, had less surface area radiating heat and had more air gap between them and the floors.

Sorry my friend, but I'd bet the farm that at least with big block b-bodies, the amount of heat transmitted
into the passenger compartment from headers is measurably higher than with manifolds.