Headers vs 360 manifolds for 318

Mopar Exhaust Systems

318 exhaust

  1. 360 manifolds

    28.0%
  2. Full length summit headers

    72.0%
  1. RustyRatRod

    RustyRatRod Weenie idiot loser. FABO Gold Member

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    I really like that thing. You did a really nice job on it.
     
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    • RustyRatRod

      RustyRatRod Weenie idiot loser. FABO Gold Member

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      I had some on a 71 Dart I drove every single day. It sat stock ride height. I never scraped the headers on anything and I drove over many speed breakers. They do hang lower than other header makes like Dougs and TTI but I knew that going in and I left the car at the stock ride height. Plenty of guys run these type headers with no trouble. Yes, if you hang your junk low in the weeds and run short tires, you're asking for trouble, but otherwise they work well.
       
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      • mopowers

        mopowers Well-Known Member

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        That's why I said- "if the car sits any lower than stock in the front, or if you have soft torsion bars." Been there, done that.
         
      • lemondana

        lemondana BlackDart

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        Make sure you run a deep sump oil pan also, then you can smash 2 things at once when you hit a speed bump, railroad tracks or that dip in the road that you did not know was there! Although I live in Nebraska where the roads are far from perfect, or best of all- that big raccoon that you hit, the big ones are really solid.
         
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        • 1Fast340

          1Fast340 Well-Known Member

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          Headers will give you more power.
          I always recomend the better ones TTI or Dougs,but for those of you who go for the cheaper headers for various reasons,make sure the car is not to low or torsionbars to soft and or worn out front shocks..
           
        • AJ/FormS

          AJ/FormS 68 B'cuda fb, Form S clone ... 367/A833/3.55s

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          Headers will give you more power. hmmmmm
          But on a 318 at 7.8Scr how much can you expect and at what roadspeed?
          When you put a bigger cam in it, the cylinder pressure will drop faster than the power will pick up. So you will be close to par from stall to 3500 or so. Then the mighty cam starts to make power; first 2hp then 5 then 9 and maybe twelve by 4800.
          But at what speeds are these increases happening at ?
          Well with 2.76s, and 26.5 tires, 3500 is about 39 mph and 4800 then is 53mph, So off the line, where most of us want the extra power............. you get nothing, unless you also install a really big TC' lol. But from 39 to 53 she cooks along pretty good in first gear
          But suppose you're hip to this and install some nasty 4.10s. Now 3500 will be around 27 mph...... and still nothing below that.
          So ask yourself, it it worth spending the money, to get the power at those higher rpms and or while also installing more gear and a bigger TC to deliver that power at the mphs as listed above?
          And then after you get that sorted, there's the small matter of the SureGrip, and the bigger tires and wheels you will need to actually go quicker.
          But I digress..................
          I didn't vote, because I wouldn't do anything to a teener until the cylinder pressure problem was overcome. Same for a 360, but now,at least you have the extra cubes
           
          Last edited: Oct 5, 2018
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          • 1Fast340

            1Fast340 Well-Known Member

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            Dont think that cam will create much problems at all.
            I like to look at a 318 as a late low compression 340 with smaller ports ,sure that cam is a few degrees larger than the 340 cam but it also has smaller/faster ports.
            I do agree however that that combination would benefit from alitle more gear,say some 3.21-3.55:1 or so gears for a driver but its not going to be entirely hopeless.
             
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            • dartfreak75

              dartfreak75 Restore it, Dont part it! FABO Gold Member

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              I didnt include it in this thread but I have a 8.8 rear with 3.73 for later. It's not high on the priority list but I know as I upgrade power the peg leg 7.25isnt gonna last.
               
            • toolmanmike

              toolmanmike FABO Staff Staff Member FABO Gold Member

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              In answer to the op's question, headers won't get you a bunch more power unless you build your combination around their performance potential. I had a stock 73 340 Challenger that I put Mickey Thompson try Y's on. I didn't change anything else on the combination. I had been running it on the strip and it actually went slower by .2 with the headers in the 1/8th than with the stock manifolds and factory dual exhaust.
               
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              • RustyRatRod

                RustyRatRod Weenie idiot loser. FABO Gold Member

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                ANYTHING you do to make it easier to get more air in and out of an engine WILL make more power. That's the long and short of it. PERIOD. Headers make it easier to get more air out. A better intake, carburetor and heads also help. Sometimes, on stock to mildly modified engines you can see a very big difference with bolt ons.
                 
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                • sireland67

                  sireland67 Well-Known Member

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                  Headers will make the engine breath better, even the cheap ones.

                  I put headers on my first duster, my ex-wife drove it for a daily driver for years, never again on a a-body.
                  Complete pain in the butt, they were blackjacks, typical cheap headers, beat to fit in place.
                  Remove to change starter etc, after a few years the drivers side was almost smashed flat from hitting on the road.

                  When I built my current duster, I used stock 340 manifolds, easy, done.
                  FYI summits pre-bent header back exhaust fits good if you take your time and trim a few pipes, I used Accurate down pipes to connect to them, all installed on jack stands in my garage.
                   
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                  • moparmandan

                    moparmandan FABO Gold Member FABO Gold Member

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                    100% agree. I'm gonna guess you were at stock ride height, too. Either way, for a street/strip or race car, sure. Cruiser? Daily driver? Nope.
                     
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                    • sireland67

                      sireland67 Well-Known Member

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                      Yes the old duster was stock ride height.

                      Current duster with manifolds will be just a cruiser / play toy.
                      You will never be able to tell the difference performance wise.
                       
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                      • 1Fast340

                        1Fast340 Well-Known Member

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                        Thats going to make a good difference both in performance and reliability!
                        Oh and since it has been brought up,the only way your car can be slower after adding a set of headers is if you fail misserably at setting up timing and carb for it especialy the carb,its not uncomon for engines to run alitle leaner after adding headers and considering how alot of cars are running alitel fat in the first place it just makes things alitle better unless your car was running perfect or alitle lean in the first place.

                        As for the isues with headers hitting the ground its either the car being to low or suspensions that are worn out unless you drive like a total jackass. A car is no longer stock height after you put some 60profile tires in the front or equivelant many seem to forget this.
                        Yes i have been there and done that shit.

                        for a comparison here comes a pic of my junk,notice the oilpan? That oilpan sits lower than headers would on a car that realy is stock rideheight and hit the ground ONCE in 4 or 5 years of driving the car everywhere,and it was due to me being real stupid one late night and it hit HARD.
                        I also ran that car with cheap headers before that and yes they dragged the ground more than once but the car was much lover at that time,i adjusted the torsionbars up when i swaped engines to the one with the deap oilpan and changed tires at the same time,in the pic it has 205/60´s i think it had 165/60s before that.
                         
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                        • 1Fast340

                          1Fast340 Well-Known Member

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                          It would have been smart to post the pic aswell. But here it goes.

                          bra bildsuddad.jpg
                           
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                          • AJ/FormS

                            AJ/FormS 68 B'cuda fb, Form S clone ... 367/A833/3.55s

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                            I hit my Milodon oil pan once, coming down from a jump,on dirt, a lil nose heavy,lol. Hard enough to crack it. After the repair work, I installed a skidplate. Good thing, cuz it is now a witness to my driving style,lol. Yeah I'm exaggerating a lil , it's not that beat-up...........
                            But I gotta tell you, when the oilpan hits dirt, for a split second,everything comes to a grinding halt. Then the suspension rebounds, pulls the pan up outta the dirt, and it's business as usual, until you stop in the pits for a look-see. This with 1.03 bars and very stiff shocks.
                            Then the track crew has to fill in the trench, and nobody brought a shovel, cuz no other competitor brought a V8 to the event, so they were not expecting mayhem..
                            I mighta won that day, if the dang dirt hadn't slowed me down so much..... I was mere seconds from winning. A couple of people still today, remember that big red flying fish.
                            So my advice is to not jump your car,lol.
                             
                            Last edited: Oct 6, 2018
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                            • Dodge73Dart

                              Dodge73Dart 1973 Dodge Dart Sport restoration

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                              So the TTI pipes bolt to the stock exhaust manifolds?
                               
                            • 318willrun

                              318willrun Roadkill '80 D150

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                              you have to give them your exhaust manifold numbers. Mine are from a B-body.
                               
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                              • leblanc

                                leblanc member 2883

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                                I would choose 3.55 gears over 3.91's.
                                 
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