Generation III Internal Engine 1997-2006 LS1 | LS6
Sponsored by:
Sponsored by:

Selecting proper head gaskets (243s)

Thread Tools
 
Search this Thread
 
Old Mar 26, 2015 | 11:49 AM
  #1  
Camarokid327's Avatar
Thread Starter
Launching!
iTrader: (4)
 
Joined: Apr 2012
Posts: 286
Likes: 25
From: Naperville, IL
Exclamation Selecting proper head gaskets (243s)

I pick up a set of 243 heads fresh from a machine shop where they received a 5 angle valve job, .005 removed for cleaning, and had the chambers smoothed.

My question is what gasket thickness would you guys recommend running to bump compression (maybe ~ 11.1) and have optimal quench all while having enough PTV clearance?

Cam: 228/228 .588/.588 112

Apologize for my ignorance, first time build and trying to wrap my head around everything I'm read in my searches.

Thanks so much in advance guys.

Last edited by Camarokid327; Mar 26, 2015 at 12:59 PM.
Reply
Old Mar 26, 2015 | 11:54 AM
  #2  
Tuskyz28's Avatar
TECH Veteran
10 Year Member
Liked
Loved
Community Favorite
 
Joined: Sep 2014
Posts: 4,892
Likes: 703
From: Mississippi
Default

What pistons is in your motor?
Reply
Old Mar 26, 2015 | 12:58 PM
  #3  
Camarokid327's Avatar
Thread Starter
Launching!
iTrader: (4)
 
Joined: Apr 2012
Posts: 286
Likes: 25
From: Naperville, IL
Default

sorry, stock bottom end.
Reply
Old Mar 26, 2015 | 03:19 PM
  #4  
Know It All's Avatar
On The Tree
 
Joined: Mar 2015
Posts: 154
Likes: 12
Default

A Cometic .040" thick x 3.910" bore would get you there. Should put you at about 11.1:1.
Reply
Old Mar 27, 2015 | 09:18 AM
  #5  
.boB's Avatar
TECH Resident
iTrader: (1)
 
Joined: Jan 2014
Posts: 897
Likes: 33
From: Colorado Springs, CO
Default

Stock deck height is about +.006-.007. Meaning that the pistons sticks out of the block about that much. A .040 head gasket gives you a quench distance of about .033-.034. That's cutting it a bit close for a stock bottom end. If you're going to keep the rpm's well below 6,000, you might be able to get away with it. Otherwise, you ruin the risk of the pistons hitting the heads.

Perfect quench is about .040.
Reply
Old Mar 27, 2015 | 09:31 AM
  #6  
96capricemgr's Avatar
11 Second Club
iTrader: (1)
 
Joined: Sep 2004
Posts: 11,975
Likes: 15
Default

Those folks in the real world understand that .033(worse case on .bob's assumptions) is just fine especially when considering the aluminum block will grow and raise the number.

.032-.035 is common in iron SBC engines turned 7000rpm.
Reply
Old Mar 27, 2015 | 01:50 PM
  #7  
Camarokid327's Avatar
Thread Starter
Launching!
iTrader: (4)
 
Joined: Apr 2012
Posts: 286
Likes: 25
From: Naperville, IL
Default

So if I run a .040 gaskets I should be good?? ( 98-02 LS1 Cometic MLS 3.910" Head Gasket .040) The car is an auto so I don't have to worry about accidentally spinning it too high.

Last edited by Camarokid327; Mar 27, 2015 at 02:08 PM.
Reply
Old Mar 27, 2015 | 09:50 PM
  #8  
.boB's Avatar
TECH Resident
iTrader: (1)
 
Joined: Jan 2014
Posts: 897
Likes: 33
From: Colorado Springs, CO
Default

Lots of factors go in to the equation: block growth, rod stretch, piston rock, etc. If you have a close tolerance race engine with new forged parts, and you can keep the temperature well controlled, you can run a pretty tight quench. Lots of race engines run 0.030-.035 quench with good results. Lots of "low" rpm truck engines also run clearances that tight with good results.

How much will a used 14 year old rotating assembly stretch at 6,000 rpm? How much will a 14 year old block grow? How much piston rock will you get at 20* or 210*? I don't know what the answers are to those questions. Are you looking for every last bit of power in a race car? or Longevity in a street car? Can you afford a catastrophic failure if you choose wrong?

Do your own research, and take your chances.
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 Mar 28, 2015 | 07:23 AM
  #9  
96capricemgr's Avatar
11 Second Club
iTrader: (1)
 
Joined: Sep 2004
Posts: 11,975
Likes: 15
Default

For a 2618 piston setup with the additional rock caused by the larger piston to wall clearance I might aim a little larger but with stock or 4032 pistons that fit tight and in older iron blocks that grow less than aluminum. .032-.035 has proven time and time again to be just fine. Yes the LS1 is a different engine but the aluminum block grows more just providing more safety.

It would be worth measuring stock just to be sure where you are now.
Reply
Old Mar 28, 2015 | 08:12 AM
  #10  
kinglt-1's Avatar
TECH Senior Member
20 Year Member
Liked
Loved
Community Favorite
iTrader: (26)
 
Joined: Jul 2005
Posts: 5,894
Likes: 254
From: Ft. Wayne, IN
Default

I will be running 61cc 243's on a stock bottom end LS1 with a 227/231 .580 .584 112 cam @ 1.85 and a cometic .045 gasket. Not sure if that helps or not.

Last edited by kinglt-1; Mar 28, 2015 at 08:20 AM.
Reply
Old Mar 28, 2015 | 07:07 PM
  #11  
voda1's Avatar
On The Tree
20 Year Member
iTrader: (4)
 
Joined: Sep 2005
Posts: 177
Likes: 1
From: Cedar Rapids, Iowa
Default

Originally Posted by Know It All
A Cometic .040" thick x 3.910" bore would get you there. Should put you at about 11.1:1.
Anyone know where to get those?
Reply
Old Mar 28, 2015 | 08:43 PM
  #12  
squalor's Avatar
TECH Regular
iTrader: (3)
 
Joined: Aug 2007
Posts: 410
Likes: 3
From: Gulf Shores Ala
Default

Originally Posted by voda1
Anyone know where to get those?
WS6 store is a sponsor here and has them in stock.
http://www.ws6project.com/user_stor/...d-gasket-040-/
$148.00 is the cost of admission.

If you want to tempt fate you can get some China copies for $50 from Speedmaster http:\\www.yourenginewillbreak.com
Reply
Old Mar 30, 2015 | 09:59 PM
  #13  
Camarokid327's Avatar
Thread Starter
Launching!
iTrader: (4)
 
Joined: Apr 2012
Posts: 286
Likes: 25
From: Naperville, IL
Default

I'm just going to stick with the stock GM MLS gaskets.

Since the heads were only cleaned up (.005) I should be able to still use my current pushrods, correct? (TSP 7.4)
Reply




All times are GMT -5. The time now is 07:39 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