Generation III External Engine LS1 | LS6 | Bolt-Ons | Intakes | Exhaust | Ignition | Accessories
Sponsored by:
Sponsored by:

1 7/8" headers worth it, 402??

Thread Tools
 
Search this Thread
 
Old Oct 22, 2008 | 08:44 AM
  #1  
rpmauto's Avatar
Thread Starter
11 Second Club
iTrader: (14)
 
Joined: May 2007
Posts: 709
Likes: 0
From: Wisconsin
Default 1 7/8" headers worth it, 402??

I was looking for some more imput on going with bigger headers. I currently have the tpis 1 3/4" long tubes, very nice coated look just like the day i put them in. Well I had them on the stock motor and now i have a 402. At the end of the build it kinda turned into budget as i completely repainted the car at the same time. I make ok power, but not as much as i was hoping for. I have tsp ls6 stg 2.5 heads. How much am i leaving on the table?? I will someday be upgrading the heads, but i want to get the most out of it with these heads. I wont do heads till i have the car dialed the way it is. Is it worth the cost for what i will gain going to the 1 7/8" headers. I think my tpis headers are a good product. I read someplace that katech used them 0n some of their motors with good success. Would i have to retune after going with bigger headers?? Thanks for your input in advance.
Reply
Old Oct 22, 2008 | 09:51 AM
  #2  
conan's Avatar
TECH Senior Member
20 Year Member
iTrader: (5)
 
Joined: May 2004
Posts: 6,492
Likes: 6
From: Back in the Burg
Default

Check this thread out. I think you would have alot to gain on a 402 with heads and the cam in your sig.
https://ls1tech.com/forums/generation-iii-external-engine/981229-stock-motor-1-3-4-vs-1-7-8-engine-dyno-results.html
Reply
Old Oct 22, 2008 | 09:54 AM
  #3  
Sales2@Texas-speed's Avatar
LS1Tech Premium Sponsor
iTrader: (5)
 
Joined: Jan 2008
Posts: 5,053
Likes: 7
From: Texas!
Default

There was a guy who went from some 1 3/4" headers (sorry I don't remember which brand) to our 1 7/8" headers on his 402 engine and gained something like 25rwhp!
__________________


Largest Stocking Distributor of LS-x Engines / CHECK OUT OUR NEW WEBSITE!

COMP - FAST - PACESETTER - DIAMOND RACING - EAGLE SPECIALTY PRODUCTS - CALLIES - COMETIC GASKETS
RAM CLUTCHES - MOSER ENGINEERING - KOOK'S HEADERS - ARP - GM BOLTS AND GASKETS - MSD - NGK
POWERBOND - ASP - AND MORE!
Reply
Old Oct 22, 2008 | 10:36 AM
  #4  
BlackScreaminMachine's Avatar
Internet Mechanic
20 Year Member
iTrader: (17)
 
Joined: May 2005
Posts: 9,830
Likes: 2
From: Wallingford CT
Default

Yea, I have seen a gain too, then that same motor on n2o runs 9.50's went to a 1-7/8 to 2" and didnt see much gain at all.
Reply
Old Oct 22, 2008 | 10:42 AM
  #5  
rpmauto's Avatar
Thread Starter
11 Second Club
iTrader: (14)
 
Joined: May 2007
Posts: 709
Likes: 0
From: Wisconsin
Default

That is what i am hoping for, if i could gain 25rwhp it would be worth the swap, I am happy with how the car runs, i am just looking for some cheaper alternatives to make the power it should.
Reply
Old Oct 22, 2008 | 10:46 AM
  #6  
slow trap's Avatar
TECH Addict
iTrader: (22)
 
Joined: Sep 2004
Posts: 2,639
Likes: 0
From: tennessee
Default

some combos gain and some may not. i'm still on 1 3/4 headers.if i knew there would be a realistic gain i would think about trying out a 1 7/8 but i just don't see my combo gainining anywhere near 20-25 rwhp. on the jug is really where a big tube helps get rid of all that extra cylinder fill so i'm still debating on the switch.
Reply
Old Oct 22, 2008 | 10:56 AM
  #7  
ndfrsd6's Avatar
10 Second Club
iTrader: (5)
 
Joined: Sep 2005
Posts: 2,141
Likes: 1
From: Homer Glen IL
Default

i had 1 3/4 hookers on my 402 with a 78mm fast from my h/c setup , i put down 475 rwhp and 440 tq. when i went to a 1 7/8 hooker and a 90/90 setup and put down 500 rwhp and 469 rwtq imo its worth it
Reply
Old Oct 22, 2008 | 11:21 AM
  #8  
06black6spd's Avatar
12 Second Club
 
Joined: Sep 2008
Posts: 185
Likes: 0
From: Manchvegas, NH
Default

Originally Posted by ndfrsd6
i had 1 3/4 hookers on my 402 with a 78mm fast from my h/c setup , i put down 475 rwhp and 440 tq. when i went to a 1 7/8 hooker and a 90/90 setup and put down 500 rwhp and 469 rwtq imo its worth it
now that is a good significant gain, wow
Reply
LS1 Tech Stories

The Best V8 Stories One Small Block at Time

story-0

Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

 Verdad Gallardo
story-1

6 Common C5 Corvette Failures and What's Involved In Repairing Them

 Pouria Savadkouei
story-2

Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

 Verdad Gallardo
story-3

Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

 Pouria Savadkouei
story-4

Top 10 Most Powerful Chevy Trucks Ever Made!

 
story-5

Hennessey's New Supercharged Silverado ZR2 Has 700 HP

 Verdad Gallardo
story-6

Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

 Verdad Gallardo
story-7

Awesome K5 Blazer Restomod Comes With C7 Corvette Power

 Verdad Gallardo
story-8

10 Camaros You Should Never Buy

 
story-9

10 LS Engine Myths That Refuse to Die

 Verdad Gallardo
Old Oct 22, 2008 | 01:01 PM
  #9  
rpmauto's Avatar
Thread Starter
11 Second Club
iTrader: (14)
 
Joined: May 2007
Posts: 709
Likes: 0
From: Wisconsin
Default

Yeah, i want to get some good n/a times with the car, but i love the jug at the track. I guess i will start saving for the next things, driveshaft, headers, rims for slicks. I am happy with the heads i got from tsp, i just will always wonder how much better an aftermarket casting would be. I am going to run with these for a few years and then maybe afr, or trick flow.
Reply
Old Oct 22, 2008 | 03:10 PM
  #10  
Tom@ARH's Avatar
Closed ex-Sponsor Account
 
Joined: Aug 2008
Posts: 257
Likes: 0
Default

I also think your setup would benfit from the 1-7/8's you'll definately need them if you spray. At this point it does'nt look like you went the cheap route. If your looking to not leave anything on the table buy the right part the first time.
Reply
Old Oct 22, 2008 | 05:52 PM
  #11  
rpmauto's Avatar
Thread Starter
11 Second Club
iTrader: (14)
 
Joined: May 2007
Posts: 709
Likes: 0
From: Wisconsin
Default

yea, i didnt go the cheap route. those tpis headers when i bought them $$$. Around $700 i think, i will have to look up the reciept. And then $300 for the crapiest y pipe setup i have ever seen. I now have a pacesetter y and it is better than the tpis one, so that doesnt say too much.
Reply




All times are GMT -5. The time now is 11:04 PM.

story-0
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

Slideshow: This heavily modified 1971 Camaro mixes classic muscle car styling with a fifth-generation Camaro interior and modern LS3 power.

By Verdad Gallardo | 2026-05-12 18:06:42


VIEW MORE
story-1
6 Common C5 Corvette Failures and What's Involved In Repairing Them

Slideshow: From wobbling harmonic balancers to failed EBCMs, these are the issues that define long-term C5 ownership and what repairs typically involve.

By Pouria Savadkouei | 2026-05-07 18:44:57


VIEW MORE
story-2
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.

By Verdad Gallardo | 2026-04-21 13:57:02


VIEW MORE
story-3
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...

By Pouria Savadkouei | 2026-04-16 10:05:15


VIEW MORE
story-4
Top 10 Most Powerful Chevy Trucks Ever Made!

Slideshow: Top ten most powerful Chevy trucks ever made

By | 2026-03-25 09:22:26


VIEW MORE
story-5
Hennessey's New Supercharged Silverado ZR2 Has 700 HP

Slideshow: Hennessey has turned the Silverado ZR2 into a 700-hp off-road monster with supercharged V8 power and a limited production run.

By Verdad Gallardo | 2026-03-24 18:57:52


VIEW MORE
story-6
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

Slideshow: A one-off sports car that looks like a vintage Italian exotic-but hides a C6 Corvette underneath-just sold for the price of a new mid-engine Corvette.

By Verdad Gallardo | 2026-03-23 18:53:41


VIEW MORE
story-7
Awesome K5 Blazer Restomod Comes With C7 Corvette Power

Slideshow: A heavily reworked 1972 K5 Blazer swaps its off-road roots for a low-slung street-focused build with modern V8 power.

By Verdad Gallardo | 2026-03-09 18:08:45


VIEW MORE
story-8
10 Camaros You Should Never Buy

Slideshow: There are thousands of used Camaros on the market but we think you should avoid these 10

By | 2026-02-17 17:09:30


VIEW MORE
story-9
10 LS Engine Myths That Refuse to Die

Slideshows: Which one of these myths do you believe?

By Verdad Gallardo | 2026-01-28 18:10:11


VIEW MORE