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454 Header Pros and Cons

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  • Rich
    After developing an exhaust leak on the right side again, I decided that maybe headers were the way to go, till I priced Thorleys at over $400 inc shipping,
    Message 1 of 3 , Aug 30, 2003
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      After developing an exhaust leak on the right side again, I decided
      that maybe headers were the way to go, till I priced Thorleys at over
      $400 inc shipping, but not inc another $100 for a heat riser valve
      that can be good in colder weather. And hardly even thinking about
      another $100 I could easily spend on getting the pipes hooked back to
      the headers. That was when I said, "hold on a minute here !!" Is this
      worth it all for an exhaust leak maybe every 20,000 miles or so that
      a $5 gasket (or a $30 surface grind w/o gasket)and a couple hours
      labor will fix ?

      And after more searching on other sites, finding more pros and cons
      on the header issue, I'm finding a lot of cons, enough so, that I
      will stay w/ the ole manifolds a while longer, or untill they crack
      or fall off. I just don't need more noise in the cab, or more heat in
      the dog house, or no noticeable improvement in milage and power
      except in the high rpm range, or to lighten my wallet by $600.

      Rich
    • Joel B. Chappell
      Rich- Well I went the $400 for the Thorley headers, and I feel it’s the best investment I have made chassis-wise except for maybe the MG starter. You don
      Message 2 of 3 , Aug 30, 2003
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        Rich-

        Well I went the $400 for the Thorley headers, and I feel it�s the best
        investment I have made chassis-wise except for maybe the MG starter. You don
        �t need the heat riser unless you�re going to do a lot of winter
        driving/camping. Over the course of four years I spent the price of the
        headers on gaskets, special cap screws from GM, machine shops, used
        manifolds to replace cracked ones, and labor. Every spring when I would take
        the rig out of storage there would be a new leak. As for the noise there is
        a lot less in the cab than with stock manifolds because they leaked and
        hiss-hissed! Granted there is a little more of a throaty sound out the tail
        pipes but it�s not objectionable while cruising down the road. I too have
        seen the cons in other conferences which are stated by, for the most part,
        guys who have no knowledge of the physics of combustion. For example;
        headers don�t generate more heat. In fact headers don�t generate heat at
        all. COMBUSTION generates heat in developing horsepower. It takes a fixed
        amount of horsepower to propel an RV down the road at 65 mph. If you
        generate that amount horsepower more efficiently, with less loss, [as is the
        case with stock manifolds vs. headers] you will do so more efficiently with
        less heat loss in the conversion process. The person that wrote that knows
        very little about the volumetric efficiency and power/energy conversion
        process in an internal combustion engine. There is less heat in the doghouse
        of my rig and it cools down faster since I installed headers. You can choose
        to lighten your wallet gradually, or in one big step, but don�t propagate
        some of the myths you see in other conferences. Take a ride in, or drive a
        454 rig that has a decent set of headers on it before you jump in and echo
        what you�ve read. You�re welcome to drive mine anytime.

        Joel in NH

        Joel B. Chappell - KC1SG
        21 Billings Street
        Milford, NH 03055

        -----Original Message-----
        From: Rich [mailto:RJgonfshin@...]
        Sent: Saturday, August 30, 2003 8:34 AM
        To: classicrv@yahoogroups.com
        Subject: [classicrv] 454 Header Pros and Cons

        After developing an exhaust leak on the right side again, I decided
        that maybe headers were the way to go, till I priced Thorleys at over
        $400 inc shipping, but not inc another $100 for a heat riser valve
        that can be good in colder weather. And hardly even thinking about
        another $100 I could easily spend on getting the pipes hooked back to
        the headers. That was when I said, "hold on a minute here !!" Is this
        worth it all for an exhaust leak maybe every 20,000 miles or so that
        a $5 gasket (or a $30 surface grind w/o gasket)and a couple hours
        labor will fix ?

        And after more searching on other sites, finding more pros and cons
        on the header issue, I'm finding a lot of cons, enough so, that I
        will stay w/ the ole manifolds a while longer, or untill they crack
        or fall off. I just don't need more noise in the cab, or more heat in
        the dog house, or no noticeable improvement in milage and power
        except in the high rpm range, or to lighten my wallet by $600.

        Rich






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      • Jim
        Correct .. they don t generate heat .. they do however radiate the generated heat. Semantics in a way. And headers are much better at radiating heat than
        Message 3 of 3 , Aug 30, 2003
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          Correct .. they don't generate heat .. they do however 'radiate' the
          generated heat. Semantics in a way. And headers are much better at
          radiating heat than cast iron. Throw in A.I.R. and you have in
          effect created combustion (heat) external to the combustion
          chamber .. similar effect with cats.

          In the turbo world it is well known that a 'thicker' manifold is
          better for that app as it 'retains the heat better than thinner
          material. Heat is power. Standard header material won't last long
          in that environ due to the excessive heat. To make a long story
          short, your standard cast iron manifold 'retains' heat much better
          than a header. At shutdown a header will cool off quicker.

          Nuff said,
          Jim



          --- In classicrv@yahoogroups.com, "Joel B. Chappell"
          <joel.b.chappell@v...> wrote:
          > Rich-
          >
          > Well I went the $400 for the Thorley headers, and I feel it's the
          best
          > investment I have made chassis-wise except for maybe the MG
          starter. You don
          > 't need the heat riser unless you're going to do a lot of winter
          > driving/camping. Over the course of four years I spent the price of
          the
          > headers on gaskets, special cap screws from GM, machine shops, used
          > manifolds to replace cracked ones, and labor. Every spring when I
          would take
          > the rig out of storage there would be a new leak. As for the noise
          there is
          > a lot less in the cab than with stock manifolds because they leaked
          and
          > hiss-hissed! Granted there is a little more of a throaty sound out
          the tail
          > pipes but it's not objectionable while cruising down the road. I
          too have
          > seen the cons in other conferences which are stated by, for the
          most part,
          > guys who have no knowledge of the physics of combustion. For
          example;
          > headers don't generate more heat. In fact headers don't generate
          heat at
          > all. COMBUSTION generates heat in developing horsepower. It takes a
          fixed
          > amount of horsepower to propel an RV down the road at 65 mph. If you
          > generate that amount horsepower more efficiently, with less loss,
          [as is the
          > case with stock manifolds vs. headers] you will do so more
          efficiently with
          > less heat loss in the conversion process. The person that wrote
          that knows
          > very little about the volumetric efficiency and power/energy
          conversion
          > process in an internal combustion engine. There is less heat in the
          doghouse
          > of my rig and it cools down faster since I installed headers. You
          can choose
          > to lighten your wallet gradually, or in one big step, but don't
          propagate
          > some of the myths you see in other conferences. Take a ride in, or
          drive a
          > 454 rig that has a decent set of headers on it before you jump in
          and echo
          > what you've read. You're welcome to drive mine anytime.
          >
          > Joel in NH
          >
          > Joel B. Chappell - KC1SG
          > 21 Billings Street
          > Milford, NH 03055
          >
          > -----Original Message-----
          > From: Rich [mailto:RJgonfshin@s...]
          > Sent: Saturday, August 30, 2003 8:34 AM
          > To: classicrv@yahoogroups.com
          > Subject: [classicrv] 454 Header Pros and Cons
          >
          > After developing an exhaust leak on the right side again, I decided
          > that maybe headers were the way to go, till I priced Thorleys at
          over
          > $400 inc shipping, but not inc another $100 for a heat riser valve
          > that can be good in colder weather. And hardly even thinking about
          > another $100 I could easily spend on getting the pipes hooked back
          to
          > the headers. That was when I said, "hold on a minute here !!" Is
          this
          > worth it all for an exhaust leak maybe every 20,000 miles or so that
          > a $5 gasket (or a $30 surface grind w/o gasket)and a couple hours
          > labor will fix ?
          >
          > And after more searching on other sites, finding more pros and cons
          > on the header issue, I'm finding a lot of cons, enough so, that I
          > will stay w/ the ole manifolds a while longer, or untill they crack
          > or fall off. I just don't need more noise in the cab, or more heat
          in
          > the dog house, or no noticeable improvement in milage and power
          > except in the high rpm range, or to lighten my wallet by $600.
          >
          > Rich
          >
          >
          >
          >
          >
          >
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          > ADVERTISEMENT
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          bin/hit?page=1
          > 374-105951838331032>
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