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1 3/4 vs 1 7/8 header?

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Old 07-20-2011, 10:01 AM
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Default 1 3/4 vs 1 7/8 header?

How much horsepower is needed before stepping up to a 1 7/8 primaries header. How much performance is lost if I buy 1 7/8 primaries header and only have 224-228 size cam?
Old 07-20-2011, 11:15 AM
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Although this subject is not without controversy I believe that 1 7/8 primaries will not lose torque or horsepower to the 1 3/4 alternative under any circumstances including stock. On the other hand the 1 7/8 may not gain a lot of torque or horsepower unless and until other modifications (heads, cams, etc.) are added to the motor.

Last edited by Darkman; 07-20-2011 at 11:36 AM. Reason: spelling
Old 07-20-2011, 11:20 AM
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Darkman is right on.1 7/8 make more power.
Old 07-20-2011, 11:31 AM
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That's what I was thinking, just wanting to make sure before I start ordering stuff..
Old 07-20-2011, 11:49 AM
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If you plan on upgrading the motor later order the parts you can grow into now. It sucks buying parts twice trust me.
Old 07-20-2011, 11:53 AM
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I agree. The 1 7/8 make a bit more power at higher RPM'S. I would just go with 1 7/8 because incase you upgrade to an agressive Heads and Cam combo or with bigger cubes you won't have to change headers later. Do the job once.
Old 07-20-2011, 12:03 PM
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Ask TSP. They sell them and they have tested them. 7/8 is your best bet
Old 07-20-2011, 12:11 PM
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Originally Posted by 415470hp
I agree. The 1 7/8 make a bit more power at higher RPM'S. I would just go with 1 7/8 because incase you upgrade to an agressive Heads and Cam combo or with bigger cubes you won't have to change headers later. Do the job once.
LG Pros made more power than Kooks 1 7/8ths.
Old 07-20-2011, 12:45 PM
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This thread was just posted the other day about how much more power the 1 7/8ths will give over 1 3/4:

https://ls1tech.com/forums/generatio...p-24-rwtq.html
Old 07-20-2011, 01:09 PM
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He also changed merge, that is not a valid comparison.
Old 07-20-2011, 04:04 PM
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What about a boosted app with 7-8 lbs (basically my setup), what would the diff possibly be?
Old 07-20-2011, 04:11 PM
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Originally Posted by JRENIGAR
What about a boosted app with 7-8 lbs (basically my setup), what would the diff possibly be?
even bigger gain

More air in+more air out= more power its basic stuff
Old 07-20-2011, 04:20 PM
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You would most likely have to repulley It to see the same boost but after that the gains should be notable.

I might add... if you are going the distance with 17/8, get a quality merge not some pacesetter or kook horse **** design.
Old 07-21-2011, 08:50 AM
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Originally Posted by 427LS7HCI
LG Pros made more power than Kooks 1 7/8ths.
I never mentioned any brand in particular of headers to use. I just said 1 7/8 was a better buy.
Old 07-21-2011, 09:18 AM
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With boost? I would run 2" primaries and a little turbo that spools quickly.
Old 07-21-2011, 09:23 AM
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Originally Posted by lemons12
He also changed merge, that is not a valid comparison.
Thats what I was wondering. Cant seem to get a staright answer in that thread
Old 07-21-2011, 09:25 AM
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tsp 1 7/8 headers buy em and dont look back
Old 07-21-2011, 09:53 AM
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1 7/8 all the way. you will def not stop modding in the future. and it wont lead to hp or tq lost anyway.
Old 07-21-2011, 12:09 PM
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Little tip for anyone getting 1 7/8 LT's.

There has never been a better, more perfect set of LT's then when Roger Grotyohan was making his headers, thats why I bought them back in 2002 for my stroker engine.

He went out of business because he started stealing from people....who knows why. But the guys headers are legendary.

He had them made at a place called Tubular Automotive. His jigs were bought by QTP.

SO.......if you want the hands down, best 1 7/8" LT's ever made......order the QTP 1 7/8" LT's. They are the Grot 1 7/8" LT's.

When Roger Grotyohan started screwing people, I was one of them. I tracked down where he had his LT's made and Tubular Automotive made me a set using his jig, thank god. Roger owed them a ton of money and they kept his jigs. Now they make them for QTP.

Good day............

*****With your cubic inches.....expect a small increase in power up top, but I bet you lose some torque.*****

.
Old 07-21-2011, 12:56 PM
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just fired my 02 ls1 with tsp 1 7/8 LT's and 3 in" ORY. short video for now.
http://www.youtube.com/watch?v=ewuQslCg9vM


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