Headers or Not..

[mopar400]

Hi Guys, need your opinion on this!

I´ve recently finished my rebuild 73 400 engine
maybe you´ve seen it under "915 heads with Hughes cam" topic..
Question: Would I benefit a lot by putting headers on it? I mean Noticable
benefit, I wont to feel it!
The build:
Ported, bigger valves 915 heads with steel shim gasket.
Hughes Muscle grind cam, In/Ex:.518 .518 , LSA:107 ,  In Dur@.050:229 , Ex Dur@.050:242
Edel perf. int manifold.
Current exhaust: all stock, no HP manifold!

Would it be worth spending the extra 1300-2000$ to get new exhaust syst. (the figures are from letting a workshop do the work!)
I´ve heard people say that on a mild build headers don´t do mouch over stock manifold true/false?

/Linus

[1BAD68]

I would say its worth getting headers, anything you can do to make the engine breath better is good. I heard headers give about 20-30 hp.
But 1300-2000 for exhaust seems pretty expensive to me. Couldn't you get a TTI kit for like 600-700 and install it yourself?

[green69rt]

Question: Would I benefit a lot by putting headers on it? I mean Noticable
benefit, I wont to feel it!  Ported, bigger valves 915 heads with steel shim gasket. Hughes Muscle grind cam, In/Ex:.518 .518 , LSA:107 ,  In Dur@.050:229 , Ex Dur@.050:242 Edel perf. int manifold. Current exhaust: all stock, no HP manifold! Would it be worth spending the extra 1300-2000$ to get new exhaust syst. (the figures are from letting a workshop do the work!) I´ve heard people say that on a mild build headers don´t do mouch over stock manifold true/false? /Linus

Just my two cents.  You didn't say if you have dual exhausts now.  If not then that would be the first thing to get.  From there this is the order I would add things (this is just my preference.) 
1. Dual exhaust.
2. Lower ratio rear, 3.23 or 3.54 for a nice street machine, higher number for a track car.
3. Headers (General rule: smaller head pipes give better low end response better for street , bigger head pipes give more top end horsepower better for racing.) Get a recommendation on this.
4. Carb. Sounds like you've done some fair work and need to match up some of the bolt on parts to complete this engine package.

[green69rt]

Forgot to add a final comment:  the only one of these that will provide a "big" seat of the pants difference is the rear end ratio change.  And I forgot one more thing, if it is an automatic trans then a high stall speed converter should be #1 on the list.

[John_Kunkel]

I hate headers on anything but a dedicated race car. The difference between headers and a set of factory HP manifolds with a good exhaust system behind them won't show any difference on the old "buttmeter".

[green69rt]

I hate headers on anything but a dedicated race car. The difference between headers and a set of factory HP manifolds with a good exhaust system behind them won't show any difference on the old "buttmeter".

I agree with John, for the cost, installation troubles and other issues that headers bring along with them, I'd look for something else to spend money on before springing for the headers.  I've had headers on a couple of cars and I can't honestly say thay made a difference unless you go to the track and run.

[Cooter]

This is just my opinion and take it for what you paid for it....

Lemme see, you build a fairly good 400, spend the bucks on getting a set of heads reworked with bigger valves to get more in, spend the bucks on getting a bigger cam, spend the bucks on a better intake manifold, yet you are gonna stick a cork right up the exhaust side?  

Headers will benefit every engine. Whether it's a low end grunt motor in a truck, or a high RPM race car.....Manifolds cannot hold a candle to headers..The only reasons they are hated so much is the fact that in the early days, the flanges were thin and warped which caused a blown header gasket almost every time you started the car..Ease of changing things like Starters/plugs when running manifolds....Todays headers like TTI have all but done away with the short comings of headers...

[flyinlow]

New yorker log style manifolds would be restictive.  If you remember your firing order, 1-8-4-3-6-5-7-2, the # 5 emptys into the log manifold, then the # 7 has to empty into an allready full manifold just 90* behind it. #8 and #4 almost as bad. At least Chrysler put the outlet to the exhuast system  between the two cylinders that fire next to each other unlike some cheby manifolds.

Cleaned up HP manifolds are an improvement.

Every street car engine is a compromise. I have headers on mine.

[Al]

After having replaced the 906 heads with the Eddy Performer rpm, vodoo cam, holley, msd and eddy performer rpm intake, I drove my 68 Charger with 383 engine for some time with the hp manifolds. The difference over stock engine was quite noticeable.

However when I replaced the manifolds with TTI complete exhaust (headers etc.) the difference became VERY noticeable, to say the least.

TTI's are expensive, but worth every cent! 

[mopar400]

Question: Would I benefit a lot by putting headers on it? I mean Noticable
benefit, I wont to feel it!  Ported, bigger valves 915 heads with steel shim gasket. Hughes Muscle grind cam, In/Ex:.518 .518 , LSA:107 ,  In Dur@.050:229 , Ex Dur@.050:242 Edel perf. int manifold. Current exhaust: all stock, no HP manifold! Would it be worth spending the extra 1300-2000$ to get new exhaust syst. (the figures are from letting a workshop do the work!) I´ve heard people say that on a mild build headers don´t do mouch over stock manifold true/false? /Linus

Just my two cents.  You didn't say if you have dual exhausts now.  If not then that would be the first thing to get.  From there this is the order I would add things (this is just my preference.) 
1. Dual exhaust.
2. Lower ratio rear, 3.23 or 3.54 for a nice street machine, higher number for a track car.
3. Headers (General rule: smaller head pipes give better low end response better for street , bigger head pipes give more top end horsepower better for racing.) Get a recommendation on this.
4. Carb. Sounds like you've done some fair work and need to match up some of the bolt on parts to complete this engine package.

Its a dual exhaust, with a cross-over,
Ok thanks for the input,
yes lower gear-ratio would be nice gonna look into that.
About carbs..my first thuoght was to keep the Thermoquad and see where it got me
I,ve heard that thay can flow pretty decently,  maybe I should get it checked and properly set.
/Linus

[BSB67]

"Would I benefit a lot by putting headers on it? I mean Noticable benefit, I wont to feel it! The build:Ported, bigger valves 915 heads with steel shim gasket. Hughes Muscle grind cam, In/Ex:.518 .518 , LSA:107 ,  In Dur@.050:229 , Ex Dur@.050:242
Edel perf. int manifold.  Current exhaust: all stock, no HP manifold!  Would it be worth spending the extra 1300-2000$ to get new exhaust syst. (the figures are from letting a workshop do the work!)  I´ve heard people say that on a mild build headers don´t do mouch over stock manifold true/false?"


If you use the cam you listed, I would go with the headers.

[mopar400]

"Would I benefit a lot by putting headers on it? I mean Noticable benefit, I wont to feel it! The build:Ported, bigger valves 915 heads with steel shim gasket. Hughes Muscle grind cam, In/Ex:.518 .518 , LSA:107 ,  In Dur@.050:229 , Ex Dur@.050:242
Edel perf. int manifold.  Current exhaust: all stock, no HP manifold!  Would it be worth spending the extra 1300-2000$ to get new exhaust syst. (the figures are from letting a workshop do the work!)  I´ve heard people say that on a mild build headers don´t do mouch over stock manifold true/false?"


If you use the cam you listed, I would go with the headers.

Ok thanks for the input, I´ll guess all be starting saving upp for some TTI´s
and concider a rear end gear-ratio uppgrade, That seems to be the difference between fast and fastest!
/Linus