Author Topic: Do Headers improve gas mileage?  (Read 3053 times)

Offline Alan

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  • Posts: 2
  • Year: 1976
Do Headers improve gas mileage?
« on: November 24, 2008, 10:34 PM »
Sent: 10/15/2000 12:43 PM

I have heard that by replacing my exhast manifold with headers I will improve my gas mileage. Has anyone here installed headers? I am thinking about installing Doug Thorley Headers. Gotta figure something to improve my 6 miles to the gallon. Is there something eles that I can do to improve my mileage?

Offline Cousin Eddie

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  • Posts: 7
Re: Do Headers improve gas mileage?
« Reply #1 on: October 03, 2013, 10:37 AM »
Sent: 10/15/2000 5:14 PM

I would stay away from the headers as long as you have good leak free exhaust manifolds. In my opinion headers can be a big pain. They can be difficult to seal and are not nearly as durable as the stock manifolds. Often they require continual maintenance. The big block truck manifold which drops straight down is a pretty good design. If you have to do something open it up with a good set of dual exhaust pipes.

I have considered going to dual 3'' pipes on my Winnie, however I am not going to change over until exhaust work is needed. Another point to consider with this change is the reduction in back pressure with dual exhaust which can mean more braking on the downgrades.

Offline Jeff

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  • Posts: 2
  • Full-Time Adventurer
  • Year: 1978
  • Make: Winnebago
  • Model: Brave
  • Chassis: Dodge
  • Engine: 440
Re: Do Headers improve gas mileage?
« Reply #2 on: October 03, 2013, 10:39 AM »
Sent: 10/16/2000 11:19 AM

Hi Alan,
As to headers, from all that I've heard they help a great deal.  However, I would have to really check into it as to adding them to the 440.  At the present time, I have dual exhaust and I believe 3 inch pipes.  I am getting between 6 and 8 mpg, closer to 8.    Thanks, Jeff

Offline UluzYarx

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  • Posts: 19
Re: Do Headers improve gas mileage?
« Reply #3 on: October 03, 2013, 10:40 AM »
Sent: 2/12/2004 4:45 PM

Headers are waste of money without straight through silencers (mufflers?).
Straight thro silencers will save petrol without headers.
Easy flow air filters will save petrol without headers.
Get you carb tuned to suit new silencers or new air filter or both.
Headers are unlikely to give you any benefit unless you seriously tune your engine.
Headers usually damage pulling power at medium and low revs.
Good luck - Dave

Offline Starbuck267491

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  • Posts: 2
  • Year: 1979
  • Make: Winnebago
  • Model: Minnie-Winnie
  • Chassis: Dodge
  • Engine: 440
Re: Do Headers improve gas mileage?
« Reply #4 on: October 03, 2013, 10:41 AM »
Sent: 2/13/2004 6:12 PM

Hi. I have fitted Headman headers and Headman freeflow mufflers to my 79 Dodge Minnie Winnie 440 cu in, the original manifolds had badly cracked and I was quoted £448 for both Manifolds here in the UK The header were £187, Muffler £60 pair, 12 ft x 2.1/2" stainless pipe £90, 2 x 90 degree bends £10, although they will not last 25 years like the original units and the bolts require checking every 400 miles due to the differant metals heat expansion, and yes the bolts do go into the water system on the heads so they must not leak each time they are checked. The engine performance on petrol is great 10 -14 mpg Uk gallon. on Lpg 13 mpg. they are a bit noisy on hills but are great at the traffic light when seeing off the VW Golfs for the first 100 yards. The other problem is you can not remove the starter moter without removing the left hand header assembly, I had to modifie the right hand header to miss the top control arm as the correct header with the correct clearance I am told was not availible any longer. I hope this gives you the for's and agaist on fitting header to your unit. Regards Joe.

Offline Oz

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  • Posts: 3197
  • "So let it be written; so let it be done!"
  • Member since: 2002
  • I own: a Motor Home
Re: Do Headers improve gas mileage?
« Reply #5 on: October 03, 2013, 10:44 AM »
Sent: 2/13/2004 8:34 PM

Thanks for the input guys,
     There was a pretty in-depth discussion on this a few months ago when I was looking into installing headers on my 440.  The benefits vs. the cost of the headers alone ($329 for the Thorleys), simply didn't justify this upgrade for me.   In addtion to the difficulties you've described, there is also the incredible heat they emit which has fried other members lines that run along the frame, necessitating the need to make and install heat shields, further complicating repair and maintenance.  I will be going with the stock manifolds and exhaust back to the muffler.  There, I will install a Dynomax Series 50 Big Bore muffler to a 3" tailpipe. 

Previously enjoyed our '74 - D24 Indian & '74 - D24 Indian Custom


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