Generation IV Internal Engine 2005-2014 LS2 | LS3 | LS7 | L92 | LS9

Upping compression on stock LS3

Thread Tools
 
Search this Thread
 
Old Nov 22, 2010 | 11:33 AM
  #1  
billyjo's Avatar
Thread Starter
On The Tree
 
Joined: Dec 2005
Posts: 126
Likes: 0
Default Upping compression on stock LS3

I have a 2010 Corvette LS3 car with about 2000 miles on it. I was thinking about milling the heads and installing thinner head gaskets to up the compression. My goal would be better mileage and slightly more power. Is it worth doing and what are the downsides?

Bill
Reply
Old Nov 22, 2010 | 07:23 PM
  #2  
severous01's Avatar
Teching In
 
Joined: Apr 2005
Posts: 39
Likes: 0
Default

milling wouldnt be worth the investment. you can do a head/cam swap. get a custom cam and get head from a lq9 or lq4...a truck engine...as they have less cc, 5 less but it's less to begin with.

and you can mill them further. but, they're the same bolt pattern, spacing and can use the tall manifold and the short manifold. mill them too far and the head ports will be too close and you'll have a hard time popping the intake on. other than that, you wont have a problem swapping truck heads onto the lsx block.
Reply
Old Nov 22, 2010 | 07:26 PM
  #3  
ChucksZ06's Avatar
TECH Resident
iTrader: (9)
 
Joined: Feb 2005
Posts: 976
Likes: 1
Default

I do not think it would be worth it by itself. You might gain 10 hp. I would do cleanup porting on the heads and put a small cam in it. A stock c6 z06 cam would probably work well if you are on a budget and want to keep it sounding stock. It is easy to get into knock problems when you get the compression above 11/1 with small cams.
Reply
Old Nov 23, 2010 | 10:02 AM
  #4  
87silverbullet's Avatar
TECH Veteran
iTrader: (11)
 
Joined: Mar 2007
Posts: 4,873
Likes: 8
From: Slidell,LA
Default

Originally Posted by billyjo
I have a 2010 Corvette LS3 car with about 2000 miles on it. I was thinking about milling the heads and installing thinner head gaskets to up the compression. My goal would be better mileage and slightly more power. Is it worth doing and what are the downsides?

Bill
You wouldn't get either by upping the compression. Just get a tune and a small cam just like Chucksz06 said and you will get your power and fuel economy.

Originally Posted by severous01
milling wouldnt be worth the investment. you can do a head/cam swap. get a custom cam and get head from a lq9 or lq4...a truck engine...as they have less cc, 5 less but it's less to begin with.

and you can mill them further. but, they're the same bolt pattern, spacing and can use the tall manifold and the short manifold. mill them too far and the head ports will be too close and you'll have a hard time popping the intake on. other than that, you wont have a problem swapping truck heads onto the lsx block.
WTF are you talking about? The heads from an lq9 or lq4 are 72cc and the ls3 heads are 70 cc. If he changed to the cathedral port head then he would have to get different rockers since his ls3 has offset rockers, then he would have to change the intake. All of that is not cost effective and most likely a power loss instead of a gain.
Reply
Old Nov 23, 2010 | 07:36 PM
  #5  
billyjo's Avatar
Thread Starter
On The Tree
 
Joined: Dec 2005
Posts: 126
Likes: 0
Default

Thanks guys, I'm not sure I'm ready to do a tune and cam swap yet. Definately not ready for that major surgery and voiding my warranty. I've only had it a couple of months. I thought if I could get a few more HP and better mileage I would do it since I can do it all myself and I don't think anyone would know.
Reply
Old Nov 23, 2010 | 09:40 PM
  #6  
severous01's Avatar
Teching In
 
Joined: Apr 2005
Posts: 39
Likes: 0
Default

sorry....it's only been about a year since i posted on here. guess i got my numbers mixed up. still....milling isnt worth it. be much better off with a cam or rockers.

if you wanna go through all the trouble of taking the heads off...have them sent out and ported....while they're out, install a cam and get a tune on the pcm.
Reply
Old Nov 24, 2010 | 09:31 PM
  #7  
redsap05's Avatar
On The Tree
 
Joined: Dec 2007
Posts: 182
Likes: 0
From: akron ohio
Default

Ls3 heads have crappy piston to valve clearence. If you mill them you wont be about run any cam bigger than 224 duration on the intake side and even that would be pushing it.
Reply
Old Nov 26, 2010 | 09:18 AM
  #8  
87silverbullet's Avatar
TECH Veteran
iTrader: (11)
 
Joined: Mar 2007
Posts: 4,873
Likes: 8
From: Slidell,LA
Default

Originally Posted by redsap05
Ls3 heads have crappy piston to valve clearence. If you mill them you wont be about run any cam bigger than 224 duration on the intake side and even that would be pushing it.
Yes, but those heads don't need much cam to make them run. They make good power with medium sized cams. I agreed with you on the milling though, its not worth it.
Reply
LS1 Tech Stories

The Best V8 Stories One Small Block at Time

story-0

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

 Verdad Gallardo
story-1

Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

 Pouria Savadkouei
story-2

Top 10 Most Powerful Chevy Trucks Ever Made!

 
story-3

Hennessey's New Supercharged Silverado ZR2 Has 700 HP

 Verdad Gallardo
story-4

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

 Verdad Gallardo
story-5

Awesome K5 Blazer Restomod Comes With C7 Corvette Power

 Verdad Gallardo
story-6

10 Camaros You Should Never Buy

 
story-7

10 LS Engine Myths That Refuse to Die

 Verdad Gallardo
story-8

Five Reasons the Camaro Was the Most Pivotal Player in the Pony Car Wars 2.0

 Brett Foote
story-9

10 Reasons the LS7 Is GM's Most Extreme Naturally Aspirated V8 Engine Ever

 Verdad Gallardo
Old Nov 28, 2010 | 11:42 AM
  #9  
Jimbo1367's Avatar
TECH Senior Member
15 Year Member
Liked
Loved
Community Favorite
 
Joined: Jul 2009
Posts: 8,029
Likes: 660
Default

Start with a tune.
Reply
Old Nov 29, 2010 | 03:05 PM
  #10  
396D1SS's Avatar
TECH Resident
iTrader: (21)
 
Joined: Feb 2005
Posts: 834
Likes: 0
From: lakeland, fl
Default

Originally Posted by redsap05
Ls3 heads have crappy piston to valve clearence. If you mill them you wont be about run any cam bigger than 224 duration on the intake side and even that would be pushing it.


I am milled .020 with a 230 duration intake runs fine
Reply




All times are GMT -5. The time now is 05:11 AM.

story-0
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-1
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-2
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-3
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-4
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-5
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-6
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-7
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
story-8
Five Reasons the Camaro Was the Most Pivotal Player in the Pony Car Wars 2.0

The world was a better place when it was still around.

By Brett Foote | 2026-01-23 09:20:37


VIEW MORE
story-9
10 Reasons the LS7 Is GM's Most Extreme Naturally Aspirated V8 Engine Ever

Slideshow: The 7.0-liter LS7 was designed for absolute cutting-edge performance.

By Verdad Gallardo | 2026-01-07 18:36:00


VIEW MORE