Headers vs. manifolds

Mopar Exhaust Systems

  1. stryker63

    stryker63 Member

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    Greetings!

    Haven't been back here for a long time (illness, job hunting, life). Have a question on my '73 Duster project.
    Engine will be a warmed-over 5.2L Magnum, question: what should I run for exhaust? I've heard the stock manifolds will not fit the A-Body engine bay without "persuasion", but any LA exhaust manifold will work (it's been suggested to me that the 340 manifolds flow almost as good as the stock units and obviously will fit my application). Should I pursue this option giving some of the problems with headers (fitment/installation issues, leaks) or is the horsepower gain worth the trouble?

    Thanks,
     
  2. K.O. SWINGER

    K.O. SWINGER Meeting in the alley since 1976

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    yes there a bit of a pain ..ok a big pain but headers are a big step up in performance and the improvement grows along with the build.after you get them in and if you uses good gaskets they don't need much maintenance.
     
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    • Treblig

      Treblig Well-Known Member

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      If you like your car riding low to the ground or if you drive where there are numerous speed bumps or dips you will learn to hate headers. The header leaks come with the territory. You only gain 7/8 horses on a mild build. If you're going all out and going to the track frequently then headers are a better choice. Good headers are very expensive.

      Treblig
       
    • Dustert73

      Dustert73 Stripping bolts since ‘10

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      Had some pretty good fitment issues with my hooker headers. They actually fit better on the driver side. Pass side was completely on the 1 inch torsion bars and the idler arm. Pain was to install/uninstall a few times to make all the necessary dents. Treblig sells some pretty killer manifolds (not sure if he has anymore left or not), which is what I'd go with if I had to do it again.
       
    • crackedback

      crackedback FABO Gold Member FABO Gold Member

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      Don't buy crappy headers and the issues regarding leaks and dragging are basically non-existant.

      Hooker and the other headers that hang below the centerlink = junk level stuff IMO.
       
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      • cuda620

        cuda620 Well-Known Member

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        I got headman tite tucks on mine. No troubles. A body smallblock.
         
      • Locomotion

        Locomotion Well-Known Member

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        Here is a 360/300hp exhaust dyno test. As mentioned, the more HP, the more headers will help. While the individul differences aren't big, those improvements are throughout the RPM range which will make an obvious difference.

        I've been using TTI's for years and they have many advantages besides the HP and torque. Easier installation, plenty of ground clearance, thicker metal, etc.

        The dyno charts are in the last pic.

        Exhaust on a Mopar 300hp Crate Engine - Tech Articles - Mopar Muscle Magazine
         
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        • AJ/FormS

          AJ/FormS 68 Formua-S fastback clone 367/A833/GVod/3.55s FABO Gold Member

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          Theres's a lot more to headers than a modest increase in horsepower. Their horsepower-effectiveness depends a lot on the rest of the combo. They also give a substantial boost in low-rpm to midrange torque, and that translates directly to mpgs. In your 73 you might get away with cheap under steering-link headers, that often barely last two years. Or you can get the good stuff that will last 4 or 5 times as long, and you never have to worry about speed-bumps again. And the thicker gauge of the good stuff has the bonus,IMO, of not sounding like a cheap,tinny,loud,header.
          If by warmed over, you mean a cam over about 225* degrees,or one with over 50ish degrees of overlap, you need headers. Even factory 340s responded well to headers, yet they had just 44* of overlap. Even my factory stock 73 teener short block, liked headers, with nothing more than a 4bbl.
          Magnums have nice heads;with a hot cam, IMO, you would be choking them with log-manifolds.
          But then again the 340 did pretty good,in stock trim.
           
        • pishta

          pishta I know I'm right....

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          Check out the bigger early magnum exhaust manifolds. They flow as good as 340's (maybe better on driver side) dont leak and are bone cheap. Mate them with a bigger headpipe and loud mufflers...sounds of headers, fit of stockers. IF they fit your steering column. Headers work but have their pitfalls.
           
        • 273

          273 Well-Known Member

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          On a mild engine I wouldn't worry about but as you try to cross 350 hp they become more important. And make the most of your mods.
           
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          • rumblefish360

            rumblefish360 I have escaped the evil Empire State! FABO Gold Member

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            Please describe "Warmed Up." With the parts being used. Do so include the trans type, stall converter speed if so equipped, rear gears and the tire size.

            IMO, and having been there and done that, there are two routes to travel for headers.

            1: Cheap typical headers and a Summit/Jegs dual exhaust.
            (Not really the recommended route.)
            Edit -> Though I do like the Jegs & Summit exhaust kits a lot, not the typical 1 size fits all header.

            2: Dougs headers or a full tti system. Both of which do not drag on the floor. Fit excellent. TTI exhaust required minor trimming to fit the wife's '67 Cuda.
            Pricey but very well worth the expense hands down.

            Sorry I can not help with the exhaust manifold issue's.
             
            Last edited: Feb 24, 2017
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            • AJ/FormS

              AJ/FormS 68 Formua-S fastback clone 367/A833/GVod/3.55s FABO Gold Member

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              My uncoated TTIs are still on the car, since 1999.How many years is that now? Cheapest headers I ever bought. They are at over 125,000 miles now...
              But the merges are leaking.
              Again.
              Not so the flange gaskets. I replaced them once in the interim, not because they needed it, but because they had been reused about 10 times already.
               
            • Dustert73

              Dustert73 Stripping bolts since ‘10

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              yup
               
            • Valkman

              Valkman Well-Known Member

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              The stock magnum manifolds will fit, and as pishta says they flow pretty good.
               
            • stroked340

              stroked340 FABO Gold Member FABO Gold Member

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              Buy the TTI's...
               
            • 318willrun

              318willrun Utube channel 318willrun

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              Had a cheap set hedmans for about 6 years on a Dart, and they were still in good shape when I sold the car..... just say'n
               
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              • ir3333

                ir3333 Well-Known Member

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                as you can see headers have 2 distinct opinions.Some will argue they don't help much and can cause a lot of grief on a street car.The other camp will argue all day... extolling their virtues.
                As always it's the combination of parts and how everything works together...I think for a 318 on the street through full length exhaust there are better places to spend your hard earned cash,like gears or converter.
                 
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                • d1970

                  d1970 TODAY IS A GOOD DAY TO HAVE A GOOD DAY

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                  For the average guy with a motor that has 300-350 horsepower and shifts at 4000, use manifolds, less problems you will have with clearances and sealing them. If you have a motor that puts out alot of horsepower and you rev it to the upper level when you shift, I would say use headers. Just my thoughts.
                   
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                  • stroked340

                    stroked340 FABO Gold Member FABO Gold Member

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                    Have used headers on every car I ever owned street strip show..exhaust manifolds were taken off and thrown in the trash where they belong..
                     
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                    • ir3333

                      ir3333 Well-Known Member

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                    • 273

                      273 Well-Known Member

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                      One thing this test shows is no need of digging up 340 manifolds 360 are fine.
                       
                    • fishmens67

                      fishmens67 FABO Gold Member FABO Gold Member

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                      Headers and dual exhaust has from day one been the first step in performance. Cams/ intakes and carbs are secondary.
                       
                    • 273

                      273 Well-Known Member

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                      To me exhaust and gears are the 1st steps to set the stage for all other mods and to take advantage of what they have to offer.
                       
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                      • stryker63

                        stryker63 Member

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                        Thank you to all who responded!

                        For Rumblefish360; engine is a ’99 5.2L Magnum. Block is bored over 0.03” with a higher duration cam (duration @ 0.05 216 intake/224 exhaust), hypereutectic pistons, heavier (LS1) valve springs, and double timing chain. Intake is a Edelbrock Performer air-gap (carb TBD). Tranny is an A904 non-lockup unit rebuilt w/Stage 1 shift kit. Rear end is an 8 1/4" unit (final gearing TBD).

                        Cheers,
                         
                      • 1Fast340

                        1Fast340 Well-Known Member

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                        Dougs And TTI Makes good quality headers that dont leak or hit the ground,fitment are usualy good but you may run into problems considering how bad the tolerances are in the first place on these cars and 40years of abuse are not helping out in that department sometimes there are probably manufacturing isues as well but i think those are rare compared to the isues with these cars.
                        Another option is Schumacher tri-y headers they dont seem to have got much attention but they sure look like a good product and considering that their bigblock headers has a nice reputation i believe the longer tri-y smallblock version might be a very nice option aswell.

                        All three will do well at your performance level and will leave you a nice bit of room for future improvements if you end up wanting more power in the future.
                         
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