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

Possible head bore problem?

Old May 20, 2006 | 07:30 PM
  #1  
KingWalrus's Avatar
Thread Starter
Teching In
 
Joined: Nov 2003
Posts: 23
Likes: 0
From: Memphis, TN
Default Possible head bore problem?

Ok, so I just purchased some Absolute Speed stage 2.5 5.3L heads from a friend. I knew he had a 370 c.i. motor, but I thought it was just stroked. I just measured the heads, and it appeard that the bores have been machined out to accomodate a 3.925" bore. Would there be any problem mating these heads to my stock bore/stroke bottom end? I'm sure it's not perfectly ideal, but I figured .02" on the diameter probably wouldn't pose a problem.

Your thoughts?

I assume it will still use a stock bore sized head gasket.

Thanks!
Reply
Old May 21, 2006 | 12:42 PM
  #2  
KingWalrus's Avatar
Thread Starter
Teching In
 
Joined: Nov 2003
Posts: 23
Likes: 0
From: Memphis, TN
Default

Anyone?
Reply
Old May 21, 2006 | 04:52 PM
  #3  
xfactor_pitbulls's Avatar
TECH Addict
iTrader: (16)
 
Joined: Jul 2004
Posts: 2,218
Likes: 0
From: Nevada, TX
Default

You should be ok. Which valves do they have? Smaller than 2.08 would be best. But even if you have 2.08s it wouldnt be bad.

Brandon
Reply
Old May 22, 2006 | 02:30 AM
  #4  
KingWalrus's Avatar
Thread Starter
Teching In
 
Joined: Nov 2003
Posts: 23
Likes: 0
From: Memphis, TN
Default

The valves measured in at 2.04/1.60. I really don't think it will pose a problem, but I'm no expert. Anyone else?
Reply
Old May 22, 2006 | 08:04 AM
  #5  
PREDATOR-Z's Avatar
TECH Senior Member
 
Joined: Mar 2004
Posts: 14,620
Likes: 17
From: BFE
Default

No you'll be fine.
Just when you choose the gasket, make sure it is at least .030 bigger that 3.925 bore.
Reply
Old May 22, 2006 | 11:43 AM
  #6  
KingWalrus's Avatar
Thread Starter
Teching In
 
Joined: Nov 2003
Posts: 23
Likes: 0
From: Memphis, TN
Default

30 thou bigger than 3.925? Why? I'll take your word on it; I'm just trying to learn in the process!

Thanks for the responses, btw.
Reply
Old May 22, 2006 | 11:58 AM
  #7  
PREDATOR-Z's Avatar
TECH Senior Member
 
Joined: Mar 2004
Posts: 14,620
Likes: 17
From: BFE
Default

Originally Posted by KingWalrus
30 thou bigger than 3.925? Why? I'll take your word on it; I'm just trying to learn in the process!

Thanks for the responses, btw.
Beacuse you do not want to shroud your chambers.
Reply
Old May 22, 2006 | 12:48 PM
  #8  
KingWalrus's Avatar
Thread Starter
Teching In
 
Joined: Nov 2003
Posts: 23
Likes: 0
From: Memphis, TN
Default

Are GM replacement gaskets available in multiple bore sizes, or would I need a cometic or something similar? I have an order placed with Scoggins Dickey on some stock gaskets, but I don't think they've shipped yet. I'll give em a call.
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 May 22, 2006 | 01:05 PM
  #9  
PREDATOR-Z's Avatar
TECH Senior Member
 
Joined: Mar 2004
Posts: 14,620
Likes: 17
From: BFE
Default

Originally Posted by KingWalrus
Are GM replacement gaskets available in multiple bore sizes, or would I need a cometic or something similar? I have an order placed with Scoggins Dickey on some stock gaskets, but I don't think they've shipped yet. I'll give em a call.
GM 6.0 are 4.060
All LS1 are 3.910 (IIRC)
Reply
Old May 22, 2006 | 01:26 PM
  #10  
KingWalrus's Avatar
Thread Starter
Teching In
 
Joined: Nov 2003
Posts: 23
Likes: 0
From: Memphis, TN
Default

So it looks like a Cometic is in my future unless the 6.0L gasket would suffice. Now if I could just get a hold of SD! ****, maybe I'll just bore the engine to match the heads. This makes sense...
Reply
Old May 22, 2006 | 01:34 PM
  #11  
PREDATOR-Z's Avatar
TECH Senior Member
 
Joined: Mar 2004
Posts: 14,620
Likes: 17
From: BFE
Default

Max safe bore on stock LS1 block is 3.905
Cometic makes a 3.970 bore

Last edited by PREDATOR-Z; May 22, 2006 at 01:41 PM.
Reply
Old May 22, 2006 | 01:49 PM
  #12  
KingWalrus's Avatar
Thread Starter
Teching In
 
Joined: Nov 2003
Posts: 23
Likes: 0
From: Memphis, TN
Default

That's interesting. Is that true for all LS1's or just the 97-98 motors? Does going beyond 3.905 require resleeving? I'm kinda surprised GM didn't put more "rebuildability" into the engine.
Reply
Old May 22, 2006 | 02:16 PM
  #13  
KingWalrus's Avatar
Thread Starter
Teching In
 
Joined: Nov 2003
Posts: 23
Likes: 0
From: Memphis, TN
Default

Ok, just talked to the guys at SD. I got some Cometic gaskets with 3.930" bore and .051" thick. I can't find the stock head gasket thickness anywhere. I swear I remember reading somewhere it being like .036" or so. This gasket is a bit thicker, but it will help with P-V clearance. These heads are milled 10 thou, and I may have them cleaned up with an additional 5 thou taken off.

Thanks for the help!
Reply
Old May 22, 2006 | 02:29 PM
  #14  
KingWalrus's Avatar
Thread Starter
Teching In
 
Joined: Nov 2003
Posts: 23
Likes: 0
From: Memphis, TN
Default

Found the factory head gasket thickness: .052". These cometic .051" gaskets will have little to no effect on quench, etc. So long as I still have some P-V clearance, I think I'm good to go.
Reply


Thread Tools
Search this Thread

All times are GMT -5. The time now is 07:47 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