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Thread: 505 BBC Headers

  1. #1
    Senior Member MASTER BUILDER
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    505 BBC Headers

    Need help I am builing a 505 BBC Dart Pro 1 heads 13.5 compression Dart intake King demon 1190 carb what size tube should i run on the headers i was thinking 2 1/8 but i dont know anyone else have any input on this?

  2. #2
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    TTT

  3. #3
    Senior Member RACING JUNKIE TheRabbit's Avatar
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    2 1/8 is a common size kit that you can build pretty easy and should work good for you.

  4. #4
    Senior Member DYNO OPERATOR
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    2.125" would be ok for decent performance with that CI assuming that you are not revving over 7000 RPM by much. 2.25" would be better if you are a NO2 guy. Either size you choose to use, be sure that you make all pipes 30" long measured from the flange, no longer, unless your engine resides in the lower rpm range like 6000 or less then 32" would be better. The smaller pipe you use meaning the 2.125", the more effective the lower end torque will be and higher the vacuum signal will be at the carb to make tuning very easy. Do not make the pipes shorter than 27" unless you rev over 7600 rpm. Good luck on your fab, headers can be a very rewarding job to do and not real complicated either. Just be sure that you do NOT drop your weld in the pipe. The inside of a pipe joint should not look like it has been welded on the inside. This will restrict air flow and make the header act like a smaller diameter. Keep the weld on the outside of the pipe only.
    Bruce

  5. #5
    Senior Member DYNO OPERATOR
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    Hey Bruce, haven't seen you post in a while! The Vette is still working great! I won a SG race in Denver on 7/3 and a 3rd Wally at a National Dragster Challenge race on 8/15. Thanks again for all your help!

    Sorry to hijack the thread,
    Johnny

  6. #6
    Senior Member MASTER BUILDER
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    Quote Originally Posted by TopspeedLowet
    2.125" would be ok for decent performance with that CI assuming that you are not revving over 7000 RPM by much. 2.25" would be better if you are a NO2 guy. Either size you choose to use, be sure that you make all pipes 30" long measured from the flange, no longer, unless your engine resides in the lower rpm range like 6000 or less then 32" would be better. The smaller pipe you use meaning the 2.125", the more effective the lower end torque will be and higher the vacuum signal will be at the carb to make tuning very easy. Do not make the pipes shorter than 27" unless you rev over 7600 rpm. Good luck on your fab, headers can be a very rewarding job to do and not real complicated either. Just be sure that you do NOT drop your weld in the pipe. The inside of a pipe joint should not look like it has been welded on the inside. This will restrict air flow and make the header act like a smaller diameter. Keep the weld on the outside of the pipe only.
    Bruce
    I did forget to mention that I am using
    NO2.

  7. #7
    Senior Member RACING JUNKIE
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    Pipes

    Quote Originally Posted by coolracing
    Quote Originally Posted by TopspeedLowet
    2.125" would be ok for decent performance with that CI assuming that you are not revving over 7000 RPM by much. 2.25" would be better if you are a NO2 guy. Either size you choose to use, be sure that you make all pipes 30" long measured from the flange, no longer, unless your engine resides in the lower rpm range like 6000 or less then 32" would be better. The smaller pipe you use meaning the 2.125", the more effective the lower end torque will be and higher the vacuum signal will be at the carb to make tuning very easy. Do not make the pipes shorter than 27" unless you rev over 7600 rpm. Good luck on your fab, headers can be a very rewarding job to do and not real complicated either. Just be sure that you do NOT drop your weld in the pipe. The inside of a pipe joint should not look like it has been welded on the inside. This will restrict air flow and make the header act like a smaller diameter. Keep the weld on the outside of the pipe only.
    Bruce
    I did forget to mention that I am using
    NO2.
    I would think a 2.250 Primary would be Just SWEET!
    Later
    G 8)

  8. Racing Junk


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