Shorty Headers vs. stock exhaust manifolds on '73 440

[GTX JOHN]

What does eye protection have to do with exhaust flow or drag racing?
View attachment 1545919

My feeble attempt at levity = Dude.

 

[AR67GTX]

I haven’t any experience with shorty headers although I have something similar on my Cobra. But my reading is they are just a no-power increase-option to manifolds for the benefit of appearance, or packaging. If power is the goal then long tube headers are the solution. Now tri-Ys are a little different I believe - not really a shorty header but more of an in-between With some additional power, but just not as much as long tube ones.

 

[Black_Sheep]

Last night I watched an episode of Nick’s Garage where he dynoed a mild 383 with long tube headers and HP manifolds, the difference was only about 20 horsepower. For a casual cruiser I’m not sure the juice is worth the squeeze…

 

[Master Gunner]

What I would really like to see is a dyno comparison between headers and hp manifolds with a full street style exhaust. Every test I've seen show the headers/manifolds just straight tubed back, not all the bends and mufflers. Then use street RPM like a 5500-6000 top end.

Mark

 

[Kern Dog]

Last night I watched an episode of Nick’s Garage where he dynoed a mild 383 with long tube headers and HP manifolds, the difference was only about 20 horsepower. For a casual cruiser I’m not sure the juice is worth the squeeze…

These seem like the words of an older guy that isn't interested in squeezing the last bit of power from his car.
A young guy would eat bologna sandwiches and wear raggedy clothes to afford the headers, work until 3:00 AM installing them, then smile as he fires it up uncorked in the garage.
Don't let yourself get old, man. Stay young and cool as long as you can.

 

[Black_Sheep]

These seem like the words of an older guy that isn't interested in squeezing the last bit of power from his car.
A young guy would eat bologna sandwiches and wear raggedy clothes to afford the headers, work until 3:00 AM installing them, then smile as he fires it up uncorked in the garage.
Don't let yourself get old, man. Stay young and cool as long as you can.

I’ve never been accused of being cool, but these and a pair of “I hate my neighbors” 3” Flowmasters will be going on the GTX in the near future…

 

[Kern Dog]

If you have a Mopar, you're probably cooler than the other guys.

 

[70bigblockdodge]

Last night I watched an episode of Nick’s Garage where he dynoed a mild 383 with long tube headers and HP manifolds, the difference was only about 20 horsepower. For a casual cruiser I’m not sure the juice is worth the squeeze…

20 horsepower is a excellent number for a bolt on external part. What other part could you bolt on and gain 6-7%.
Magic spark plugs? Yeah, seriously
Bigger Carburetor? Now your affecting low speed drivability
Blower? That would give you quite a gain, but far from simple bolt on, and your 9.5:1 compression is not going to play nice with pump gas and exhaust manifolds.
Exhaust is a wash, whatever percentage it takes away with headers is going to be the same or worse with manifolds. Hot high pressure gasses being shoved into a 2 1/2" pipe at 4-12" inches away from where it leaves the port is worse than it having 18-30" to speed down a pipe cooling as it goes before getting stuffed in the 2 1/2" pipe.
At a lousy 4500 rpm there are 150 exhaust pulses per second in your left or right exhaust manifold or header.

 

[Master Gunner]

The thing to remember is that it's not 20 hp increase across the board, it slowly builds as RPM increases. Something to remember in a pure street car is what is going to be your top RPM, and how often you plan on getting there. 20 hp at 6000 doesn't really matter if you don't intend to spend much time above 4500-5000 RPM.

Bottom line, build for what you want the car to do (plus alittle fun factor), and enjoy the ride.

Mark

 

[GTX JOHN]

That is exactly Correct.
We are talking about a street car that will probably never
see the track according to the poster.

We design/test/build our own proprietary design header for our
Stock and Superstock cars. Most of the benefit of the tuning are
lost in a car that has a full exhaust system in a street application.

 

[Black_Sheep]

That is exactly Correct.
We are talking about a street car that will probably never
see the track according to the poster.

We design/test/build our own proprietary design header for our
Stock and Superstock cars. Most of the benefit of the tuning are
lost in a car that has a full exhaust system in a street application.

In the Nicks Garage episode the headers and manifolds were almost the same until 3500 rpm.

Power nation did a dyno comparison between 2.5” and 3” using a full exhaust system, that was interesting as well.

 

[70bigblockdodge]

In the Nicks Garage episode the headers and manifolds were almost the same until 3500 rpm.

So to all the guys that hate headers, love reproduction 14" bias tires and want 3.55 or better gears "to give some punch off the line" when exactly are you below 3500 rpm?
My Challenger has 3.23 and my never seem to wear out 225/70r14 tires and I'm at 3400 at 70mph.
I guess in your driveway and pulling into Dairy Queen with the grand kids.

 

[BSB67]

These posts come up every 6 months or so.

I cannot remember seeing or hearing a true apples to apples comparison with all of the set-up details. Not all 400 hp motors are created equal. Motor build details matter. Nick's 18 hp on a 400 hp 383 with a mild (4.7% for those that are math challenged), small overlap cam sounds about right. Those were 1 7/8 tube long tube headers, but of course, without the exhaust system. On a different 400 hp 383, the header/manifold difference might 30 hp.

The OP simply has to decide. If you are building the motor now, and you want 400 - 500 hp, it is easy without headers if you don't want headers. The TTI 1 7/8 Headers will cost $1,100. You can use those $$'s elsewhwere in the motor to make more power. If you have a motor that is already complete, your options are more limited on where to spend $1,100 for more power.

 

[496 polara]

And I bet 1 3/4 headers on that 383 would have been a better fit for that motor.I will guess that it may have helped lower rpm torque numbers even more.

 

[BSB67]

And I bet 1 3/4 headers on that 383 would have been a better fit for that motor.I will guess that it may have helped lower rpm torque numbers even more.

maybe even 1 5/8"

 

[racerx20]

This article should be plastered across the top of this sub-forum.

https://www.motortrend.com/how-to/mopp-0106-manifolds-vs-headers/

Headers make more power than manifolds. I've used TTI long tubes and now on mid-length Hedmans unless it's a 100% matching numbers stock resto go with headers that you like.

 

[BSB67]

No one has questioned that headers make more power.

The referenced article is exactly what I’m referring to in my above post. It’s not applicable to the OP question and has far too little information to draw any meaningful conclusions for any application.

 

[GTX JOHN]

No one has questioned that headers make more power.

The referenced article is exactly what I’m referring to in my above post. It’s not applicable to the OP question and has far too little information to draw any meaningful conclusions for any application.

Agreed!

We are talking about a very mild 440 engine (400HP) the early 440 were
rated 375 HP / Carter Four Brl. and 390 Six Pack as delivered. According to the OP it is
in a mild street car/daily driver and the 73 440 was an extremely low compression engine ( .120
down from deck as opposed to earlier 68/69 @ .027 and 70/71 440/6 nearly flush deck ).

Absolutely no one disputes that manifold are restrictive in a modified high HP engine.
Proportionally more so as HP and compression increase BUT that is not what
the OP is inquiring about! Apples to Oranges comparison.

My 69 Valiant (Mopar Muscle cover car) with a mild 440 (Home ported 906's /9.5 compression/228 @ 50 hydraulic)
ran in the 11's in street trim up here at LVMS Altitude with the old C Body log manifolds (Only manifold that would fit). I drove
it anywhere I wanted and I think that would please most daily drivers for performance in a street car. It did pick up
about a .15 with the TTI two inch headers as driven thru the mufflers BUT they were a $1,000.00 bite in the old wallet.