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Thread: SBC 1 3/4 TO 1 7/8 HEADERS

  1. #1
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    SBC 1 3/4 TO 1 7/8 HEADERS

    How much gain,if any, would a set of 1 3/4 to 1 7/8 headers over a set of 1 3/4 hooker super comp headers on a 383 sbc,13-1,dart iron eagle 215 platinums,super victory,comp flat tappet,.558 550,260,[email protected] 108,alky 750 carb,3100 lb camaro?

  2. #2
    Senior Member MASTER BUILDER
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    How much r u reving this puppy

    At low end rpm u will lose hp and if u r reving it over 7500 rpm then u will gain hp in the top end.......if u r reving it to 7000-7200 rpm stay with the 1 3/4 headers

  3. #3
    Senior Member RACING JUNKIE jmarksdragster's Avatar
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    Keep the 1 3/4. There are better places to gain from, and your engine would probably lose power.
    Mark Whitener
    http://racingfuelsystems.myfunforum.org
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    Good work isn't cheap, and cheap work can't be good.

  4. #4
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    Thanks for the info guys,I'm going to stick with the 1 3/4

  5. #5
    Junior Member SHOW GUEST
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    this is alittle more complicated than all that has been said. rpm matters but the heads you run and cubes as well as compression. stepped headers help with port velosity and can increase hp a handfull in the right situation....my 2 cents
    drive it out the door

  6. #6
    Senior Member MASTER BUILDER
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    Instead of the ex you may want to try shortening up your cam. alky burns slower than gas developing peak cyl pressure with the crank farther from TDC on that size engine we have found anything on the ex beyond 260 @ .050 will loose a lot of low end torque. by dropping the ex duration to 260 i wouldn't be surprised if you picked up 50 lbs torque @ 4000 rpm.Bill
    Hendrens Racing Engines
    1310 U.S. Hwy 221 North
    Rutherfordton N.C. 28139
    828-286-0780 Bill, Steve, Mike
    www.hendrensracingengines.com

  7. #7
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    Great info Bill-I actually had spoke to many cam company's and they all wanted me to install a BIG cam,example anywhere from 274 to 284 @.050 on the exhaust.I only have a 4800 converter and use a 9x30 slick,so I had the cam I use,comp,ground to my specs,which is listed in the first post.I added a little more on the exhaust to kill some torque because of the small tire.I've only got to run at my home track once,which was 92* and 4,000 ft corrected altitude since new motor and it ran [email protected]

  8. #8
    Senior Member MASTER BUILDER
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    When my shop was in California we did two years of cam testing related to 360/388 cu.in engines on alky.we had a racer at a local track that thought he would get on up on local engine builders and he bought a $30,000.00 engine that was supposed to be designed for alky from a well known cup engine builder. after three weeks of not making the main he brought the engine to me to dyno. the engine had decent power @ 7500rpm but no torque @ 4000. his cam was 264/276 we changed cams to one of the alky grinds we had in the shop 258/260 and made the same top end power with a 100 lb torque increase at 4000 Rpm. bottom line is alky loves comp ratio but not long ex duration.Bill
    Hendrens Racing Engines
    1310 U.S. Hwy 221 North
    Rutherfordton N.C. 28139
    828-286-0780 Bill, Steve, Mike
    www.hendrensracingengines.com

  9. #9
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    Bill do you know George Koppel?How much ignition timing did you run on the 383's?

  10. #10
    Senior Member RACING JUNKIE jmarksdragster's Avatar
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    Bill, do you think it liked the intake and exhaust close together or was it an overall lower duration? Less time to vent exhaust might retain a little more heat?
    Mark Whitener
    http://racingfuelsystems.myfunforum.org
    __________

    Good work isn't cheap, and cheap work can't be good.


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