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1 3/4'' or 1 7/8'' headers?

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Old 06-13-2012 | 12:55 PM
  #21  
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setup in the sig... 1 3/4's here... don't see where they are limiting my potential..
Old 06-13-2012 | 01:53 PM
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Thanks guys...The manufactures recommend 1 7/8 for 500+ hp, and since im planning on comin in a little under that i dont think 1 3/4 will hurt...
Old 06-13-2012 | 02:49 PM
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Originally Posted by LS1Sacrelig
Thanks guys...The manufactures recommend 1 7/8 for 500+ hp, and since im planning on comin in a little under that i dont think 1 3/4 will hurt...
PM Sent!

Chad
Old 06-13-2012 | 07:06 PM
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Originally Posted by therabidweasel
That comparison used two different header designs and showed something like +7/+5 at 6500rpm at the crank. At 3000rpm HP was the same and torque was -6. The weird thing was that the -6 was called insignificant while the +5 was significant. Bottom line is it was an apples to different apples comparison that showed moderate if any increase. Not a terribly compelling argument for 1 7/8 imo.
Part of that test makes no sense. How can you have the same horsepower at 3000rpm yet the torque is different. That is not how it works.
Old 06-13-2012 | 08:07 PM
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I have never seen 1 7 /8 header break 500rwh but I have seen the 1 3 / 4 LT's break 500 w/ h / c / i. So....
Old 06-13-2012 | 08:27 PM
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For what it's worth I've seen multiple threads on here where venders have said factory head with small valves benefit from 1 7/8 primaries and after market heads with bigger valves might be better off with 1 3/4.

Check out this thread

https://ls1tech.com/forums/dynamomet...-only-ls1.html

After the intake swap he switched to 1 7/8 headers. He only gained 9 peak hp but gained a bunch of torque across the curve
Old 06-13-2012 | 09:00 PM
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very interesting..
Old 06-13-2012 | 10:30 PM
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https://ls1tech.com/forums/dynamomet...s-1-7-8-a.html

https://ls1tech.com/forums/generatio...o-results.html

I'm not trying to debate here or refire an old debate. This is all FYI on my part. I was given 1 3/4" as a gift from my girl, they are going on...but I'm also mamofied.
Old 06-13-2012 | 11:49 PM
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^^^ I assume the gains from 1 7/8 come from Cam setup... Buying bigger header will give u room to grow
Old 06-14-2012 | 08:35 AM
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Looks like I will be selling my 1 3/4 Kooks with a fresh Jet Hot coating. Headers havent been ran since I had them coated. Sterling Silver still shining inside & out!
Headers were ran for about 12k miles uncoated before taking them off. I am building a new motor so I sent them to Jet Hot to be coated and they have been waiting on me to finish the build.

I plan on putting them on the Parts Classified probably this weekend. $500 plus shipping and fees for used headers with a brand new coating. Again, the headers have not been ran since the coating.

Great thread, now to find 1 7/8 headers for my 550+ RWHP project!!

Chad
Old 06-14-2012 | 09:04 AM
  #31  
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Originally Posted by ss4chad
Looks like I will be selling my 1 3/4 Kooks with a fresh Jet Hot coating. Headers havent been ran since I had them coated. Sterling Silver still shining inside & out!
Headers were ran for about 12k miles uncoated before taking them off. I am building a new motor so I sent them to Jet Hot to be coated and they have been waiting on me to finish the build.

I plan on putting them on the Parts Classified probably this weekend. $500 plus shipping and fees for used headers with a brand new coating. Again, the headers have not been ran since the coating.

Great thread, now to find 1 7/8 headers for my 550+ RWHP project!!

Chad
Pm sent.
Old 06-14-2012 | 11:10 AM
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Headers sold, buying 1 7/8. Thanks for the info in this post, great info for my build!

Chad



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