magnum manifolds

Mopar Exhaust Systems

  1. 93ragtop

    93ragtop Well-Known Member

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    I have a set of manifolds off of a 2000 ram 5.9. The opening is 2in. The motor is a stock 2000 5.9 other then a carb conversion.....
    Reading on this site, dual 2.5 in. exhaust seems to be the recommended size.
    My question is, are most of you converting the 2in to 2.5in at the manifold?
    If so, is there much being accomplished with the 2.5 in. exhaust?
    Assuming there is, how restrictive would it be to run about 2 ft of 2in pipe, then upsize to the 2.5?
    It's going in a 87 4wd dakota, and space for the 2.5 is tight.
    Thanks for your opinions.
     
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    • Garrett Ellison

      Garrett Ellison Amateur driver on public roadway, do not imitate.. FABO Gold Member

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      There were two sizes of spigot outlets on magnum manifolds. The early was 2-1/8 and the later was 1-7/8. The common modification concerning magnum manifolds (with an a body anyway) is using a right hand manifold and boring the 2-1/8 outlet to 2-1/4 inches. I’m a little fuzzy on the stock exhaust pipe size for which manifolds at the moment, but I’m pretty sure that the modified early manifold makes use of a 2-1/4 inch pipe and the later manifold uses 2 inch pipe stock.
       
      Last edited: Oct 18, 2020
    • Treblig

      Treblig Well-Known Member

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      Would you mind posting good pics of the 2000 Ram 5.9 exhaust manifolds, with measurements of the outlet? Please include pics of the casting number. I try to keep track of the larger manifolds and have never seen a 2 inch outlet 2000 manifold. I'm sure they exist, I've just never seen one. Thanks
       
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      • Hellrats

        Hellrats Just another dumbass FABO Gold Member

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        This is what I did on one of my "A" body cars because headers can be a pain in the a$$ on a street car. 2" just enough to get past the steering then it necks up to 2.5" the rest of the way back. I'm running 318 manifolds that were opened up as much as possible. Runs great too!
         
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        • 93ragtop

          93ragtop Well-Known Member

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          Mine are the smaller ones.... I thought the only larger ones were on 92-93 magnums. 94 forward were all the same both 5.2 & 5.9.
          I guess my post is a little misleading. They are the 1&7/8? But I think the pipe measures 2in. OD
          Below are pictures. Oh, and for the same reason, wanting manifolds..... Headers for the early Dakota 4wd only seem to be shortys and they come with the flange to hook up to the stock y pipe.
          Thanks to everyone, and here are the pictures.

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          • Treblig

            Treblig Well-Known Member

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            Yep, those look like van/truck manifolds. The passenger's side will work on an A body but because of the design the passenger's side exits close to the fire wall/foot board. They'll work just fine. Don't know about the driver's side but I think other FBAO member's have made minor mods on the driver's side to make them work. The biggest (2 1/8") manifolds were made in 92/93 but then in 96/97/98 they were also used on the Jeep Grand Cherokee. Unfortunately the driver's side off of the JGC won't work on an A body but the passenger's side fits better than then factory manifolds!! The larger 2 1/8" manifolds were also used on some trucks and vans but aren't as popular (design differences) as the JGC manifolds. You can buy a JGC 2 1/8 manifold for 25-45 bucks!!
             
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            • Stephen Hotz

              Stephen Hotz Youtube channel Stephen Hotz FABO Gold Member

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              Passenger side truck manifold made contact with my transmission dipstick handle otherwise it fit as stated.
               
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              • scott mattingly

                scott mattingly Active Member

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                Gents,
                I am currently having my 360 engine rebuilt for my 74 Duster (Manual steering/brakes and floor shift auto) and making preps to reinstall with different exhaust. Previously had a set of long tube headers that had been badly scraped on ground by previous owner and damaged. I liked the sound/look of the headers but didn't like trying to work around them all the time and the heat they generated.
                I am thinking about shifting to a simple set of manifolds on re-install of the engine as I primarily just cruise in it (and lay some rubber once in a while). After researching at Summit Racing for a set of the stock, HUGE, log-type car manifolds, I found this thread and much prefer the shape and look of these 90's era magnum truck/dakota style manifolds. From what I read above, I believe I can expect these to fit on my Duster w minimal problems. IS THAT RIGHT? The Dorman brand manifolds I found at Summit are listed as having 2-1/8" openings which seems reasonable to me.
                Any advice? Anticipated problems? (I did see Stephen's note about potential contact with trans dip-stick). Engine block is an early 70's with factory heads.
                THX -Scott
                 
              • Treblig

                Treblig Well-Known Member

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                I just went to Summit and didn't see a 2 1/8" Dorman manifold for 360s??? P/N ??
                 
              • scott mattingly

                scott mattingly Active Member

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                Trebling,
                I was more interested in whether folks on the forum believe these would fit my 74Duster without complications. Anyone?
                Your Information/link is below. The outlet size is discussed in a customer's question on this product at Summit's site. If you can't find it, the answer states:
                "...Dorman 674-271 exhaust manifold has a 2.125 in. outlet diameter..."
                I realize this answer might be referring to the outside diameter of the down-pipe that fits this manifold which would indicate an I.D. of closer to 2". I am O.K. with either dimension but will probably just submit a new question for clarification before I make a purchase.
                -Scott

                Dorman 674-271 Dorman Exhaust Manifolds | Summit Racing

                Exhaust Manifolds 674-271 (Driver's side)
                the Passenger side is# 674-270
                 
              • Treblig

                Treblig Well-Known Member

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                For that price (or less) you could get a "real" 2 1/8 magnum manifold that will fit your car perfectly. If you like, go here:
                Car-Part.com--Used Auto Parts Market
                Type in 97 Jeep Grand Cherokee Passenger's manifold and you'll get many, many original manifolds. You can have them listed by price or by distance (from you). You might even find one nearby!! FYI- I've called many of the places that didn't list a price and bought some for as low as $25 so don't hesitate to call and ask if no price is listed.
                 
              • 67Dart273

                67Dart273 FABO Gold Member FABO Gold Member

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                I have never understood, why a "company" which built some incredibly beautiful manifolds for hemis and the B/RB stuff never built a decent performance exhaust for the small blocks!!!
                 
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                • Hellrats

                  Hellrats Just another dumbass FABO Gold Member

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                  ^^^ A bodies are the worst ^^^ Lots of room in an E body. They run damn good but yea the exhaust system can be a bit of a battle.
                   
                • Hellrats

                  Hellrats Just another dumbass FABO Gold Member

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                  To the OP, if it's going into a 4x4 just make it fit. There is no room in those trucks anyway. Sounds like it going to be street driver? You won't gain much between 2" and 2.5" as there is a lot of shit to get around. I'd keep it simple. Anything Dakota 4x4 is a pain to work on. If I remember right the exhaust was the same size on a R/T back to the CAT anyway. I just put and exhaust on a 1997 3.9 2WD Dakota and I was surprised to see the listing for all 2WD trucks where the same. So anything that will fit is good. Just try not to crimp anything. If you look at a stock y-pipe it is total shit the way they smash it to fit. Go 2" if you can make it fit and you will be custom making the rest. I tried a set of block huggers on a 1995 Dakota with a 318. They did not fit will. It's going to be custom anyway you look at it.
                   
                • des69mopar

                  des69mopar Active Member

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                  So do the JGC flow as well as the 92/3?
                   
                • MOPAROFFICIAL

                  MOPAROFFICIAL FABO Gold Member FABO Gold Member

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                  Be nice to know of anyone who tried the carb apprroved shorty headers w/outlet in stock location for mag trucks ..in an a body.
                  Since the manifolds fit, is there room?
                   
                • Treblig

                  Treblig Well-Known Member

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                  I don't see why they wouldn't be about the same if not better. The JGC was also used on the 360 engine. They both have the same exit hole diameter and they both can be hogged out to over 2 1/4".
                   
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