Header size ?

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Header size ?

Post  whitefield on August 26th 2015, 12:15 am

Suggestions on header size for a 408W with 205AFR heads and 13.1 compression solid roller cam max rpm 7500 Vic jr intake and 950 carb. 1"7/8 or 2" primary tube headers ?
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Re: Header size ?

Post  gmsmkr on August 26th 2015, 12:21 am

2" gets my vote
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Re: Header size ?

Post  supervel45 on August 26th 2015, 6:32 am

1 7/8"

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Re: Header size ?

Post  gmsmkr on August 26th 2015, 7:46 pm

1 7/8 headers belong on a motor with 10.1 comp ..... not a 13.1 408w in race trim
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Re: Header size ?

Post  rmcomprandy on August 26th 2015, 10:25 pm

whitefield wrote:Suggestions on header size for a 408W with 205AFR heads and 13.1 compression  solid roller cam max rpm 7500 Vic jr intake and 950 carb. 1"7/8 or 2" primary tube headers ?

If that engine ever drops below 6,000 RPM use the 1 7/8" primary tubes.  Above 6,800 RPM will be the only place the 2" tube will be better.

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Re: Header size ?

Post  whatbumper on August 26th 2015, 10:41 pm

NA, the 1 7/8" will probably be faster but the 2" will make more power. With those heads.

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Re: Header size ?

Post  FalconEh on August 26th 2015, 10:57 pm

Long tube headers I would assume ...with a N/A combo at 7500, guessing 3" or 3 1/2" collector with a min. 3" exhaust or no exhaust, I would use the 1 7/8" ...if you want to spray it use the 2". The heads will flow more but like Randy said 700 RPM is not the majority of the pass when you limit it to 7500.
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Re: Header size ?

Post  whitefield on August 26th 2015, 11:59 pm

rmcomprandy wrote:
whitefield wrote:Suggestions on header size for a 408W with 205AFR heads and 13.1 compression  solid roller cam max rpm 7500 Vic jr intake and 950 carb. 1"7/8 or 2" primary tube headers ?

If that engine ever drops below 6,000 RPM use the 1 7/8" primary tubes.  Above 6,800 RPM will be the only place the 2" tube will be better.


5000 stall . I limited it to 7500 rpm due to having a stock 74 block . I thought about turning it on up to 7800 or 8000 RPM. NA engine.
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Re: Header size ?

Post  whitefield on November 28th 2015, 12:02 pm

I ordered the 1 7/8 with 3" collector long tube kooks headers . Thanks for all of the replies!
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Re: Header size ?

Post  johndickjr on January 20th 2016, 9:28 pm


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Re: Header size ?

Post  maverick on January 20th 2016, 11:17 pm

That video is a hoot and a shocker. Laughing
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Re: Header size ?

Post  res0rli9 on January 20th 2016, 11:25 pm

maverick wrote:That video is a hoot and a shocker. Laughing

& easy hp. lol

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Re: Header size ?

Post  johndickjr on January 21st 2016, 7:22 am

cousin had a vega with a decent 406 sbc in it, it had 1-1/2 tubes, ran 11.00, finally got some big hp building tubes for the car , thinking the was lemons maybe, like $1000, 1-3/4 or 7/8 tubes, merge collector , all the tricks..car ran 11.00 after wards, my headers are my car are beat to shit, 1-3/4 it runs 6.60s, maybe ill dent it some more

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Re: Header size ?

Post  supervel45 on January 21st 2016, 9:57 am

Oh hell, next someone will say single pattern cams are good. Wink

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Re: Header size ?

Post  dfree383 on January 21st 2016, 10:18 am

supervel45 wrote:Oh hell, next someone will say single pattern cams are good. Wink

Everything has its application........ most build with their wallet not their brain.
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Re: Header size ?

Post  torino501 on January 21st 2016, 10:59 am

how bout a stepped header, 1-7/8 into a 2"...?

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Re: Header size ?

Post  wickettoby1 on February 3rd 2016, 12:23 am

johndickjr wrote:

I'd rather have a maple syrup enema and sit on an ant hill then deal with David Freiburger on a daily basis!

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