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

Mac Headers and ORY..Hp Increase? How much?

Thread Tools
 
Search this Thread
 
Old Apr 5, 2006 | 08:36 PM
  #1  
98SS Blackattack's Avatar
Thread Starter
TECH Fanatic
 
Joined: Jun 2002
Posts: 1,227
Likes: 0
From: Indianapolis
Default Mac Headers and ORY..Hp Increase? How much?

Finally ready to put them on. Have been putting it off for months.
I have Stock Manifolds and cats now. How much power should i expect to pick up?
Reply
Old Apr 5, 2006 | 08:56 PM
  #2  
Demon Of Dreams's Avatar
TECH Enthusiast
iTrader: (3)
 
Joined: Mar 2006
Posts: 714
Likes: 0
From: Houston...
Default

25hp
Reply
Old Apr 5, 2006 | 09:31 PM
  #3  
98SS Blackattack's Avatar
Thread Starter
TECH Fanatic
 
Joined: Jun 2002
Posts: 1,227
Likes: 0
From: Indianapolis
Default

Seems a bit high...anyone else?
Reply
Old Apr 5, 2006 | 10:22 PM
  #4  
FHAWKer's Avatar
Teching In
 
Joined: Jun 2005
Posts: 27
Likes: 0
From: Daytona Beach, FL
Default

At best 15-20rwhp if you have a non-restrictive cat-back. Of course if you have a blown and heavly cam'd motor, then you might get near the advertised gains...on a good day.
Reply
Old Apr 5, 2006 | 10:40 PM
  #5  
jlrz28's Avatar
10 Second Fun Car
iTrader: (7)
 
Joined: Nov 2002
Posts: 2,045
Likes: 1
From: Pearland, Tx
Default

15-25, just depends on what else you have done and what kind of cats your using and also your exhaust
Reply
Old Apr 5, 2006 | 10:51 PM
  #6  
b00sted's Avatar
TECH Fanatic
20 Year Member
iTrader: (7)
 
Joined: Jun 2005
Posts: 1,109
Likes: 0
From: Chicago
Default

Yeah somewhere around 20...Run a dynamouth with it or stock catback and a cutout...
Reply
Old Apr 6, 2006 | 05:12 PM
  #7  
98SS Blackattack's Avatar
Thread Starter
TECH Fanatic
 
Joined: Jun 2002
Posts: 1,227
Likes: 0
From: Indianapolis
Default

I have a Loudmouth Catback. Cats will be gone.
Reply
Old Apr 6, 2006 | 08:03 PM
  #8  
INMY01TA's Avatar
11 Second Club
20 Year Member
iTrader: (1)
 
Joined: Apr 2003
Posts: 3,235
Likes: 2
From: Crofton Md.
Default

I got the Mac's and ORY, you'll notice it.
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 Apr 6, 2006 | 11:52 PM
  #9  
Redneck Z's Avatar
TECH Addict
iTrader: (3)
 
Joined: Feb 2005
Posts: 2,305
Likes: 2
From: Citrus Heights, CA
Default

On a SI car, probably 12-15rwhp.
Reply
Old Apr 8, 2006 | 05:03 PM
  #10  
98SS Blackattack's Avatar
Thread Starter
TECH Fanatic
 
Joined: Jun 2002
Posts: 1,227
Likes: 0
From: Indianapolis
Default

Thanks guys. Im putting on the Mac's and an FMS F4 cam so i hope to see around 40-50 HP gain. The Cam is a .226/.594 lift
Reply
Old Apr 8, 2006 | 09:38 PM
  #11  
Drew's TA's Avatar
On The Tree
 
Joined: Apr 2005
Posts: 144
Likes: 0
From: McKinney (Summer)/Stillwater (school)
Default

I gained 25hp with MAC headers. with lid and loudmouth I had 300 even then after just the headers and catted y-pipe it jumped up to 325
Reply
Old Apr 8, 2006 | 10:16 PM
  #12  
Dip Stick's Avatar
TECH Resident
iTrader: (1)
 
Joined: Jul 2004
Posts: 854
Likes: 0
From: Henderson, NC
Default

Not sure what I had bone stock :0 but in my sig shows what I had with catted y-pipe and mac mids. The nly thing that seemed to change with the mac's is I lost some low end torque. I've done no chasis improvements, and the sexy twisting the car used to do during a hard 1-2 shift and on some 2-3 shifts was pretty much gone

The sound is insane Shrugs

Im getting a 228R installed soon, and optedn to go with pacesetter LT's..

Still using my borla catback, but Might go with a magnaflow.. to tame the sound down a little.
Reply
Old Apr 9, 2006 | 03:14 AM
  #13  
Benjamin Russick's Avatar
TECH Fanatic
iTrader: (1)
 
Joined: Nov 2001
Posts: 1,493
Likes: 0
From: Chesapeake, VA
Default

I'd say a good 20rwhp with the ORY. Make sure you clean up the welds and I'd lose the ball-flange and weld in a Hooker collector.
Reply
Old Apr 17, 2006 | 08:34 PM
  #14  
UMD_Jesse's Avatar
TECH Apprentice
20 Year Member
iTrader: (6)
 
Joined: May 2003
Posts: 377
Likes: 0
From: Fairfax County, VA (You know you're here when you see the bad roads)
Default

What kind of ground clearance do you get with MAC y?
Reply
Old Apr 17, 2006 | 08:44 PM
  #15  
jlrz28's Avatar
10 Second Fun Car
iTrader: (7)
 
Joined: Nov 2002
Posts: 2,045
Likes: 1
From: Pearland, Tx
Default

Ground clearance is great but it has been known to bang on the drivers side. This is similar to what I used on mine to fix all the problems http://www.thunderracing.com/catalog...id=528&pcid=54
Reply




All times are GMT -5. The time now is 12:22 AM.

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