417 Head Gasket size - LS1TECH - Camaro and Firebird Forum Discussion

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

417 Head Gasket size

Reply

Old 04-16-2018, 08:51 PM
  #1  
11 Second Club
Thread Starter
iTrader: (8)
 
black02-z28's Avatar
 
Join Date: Nov 2003
Location: Nashville, TN
Posts: 498
Default 417 Head Gasket size

Looking for a double check here, I have a 417 LS3, 4.075 bore, 4.0" stroke. Pistons are -10cc dished.

Advanced Induction has finished up my heads, 280cc with a 75cc chamber.

I want to run thinner heads to keep compression up.

Cometic .040 comes in 4.100 bore, that'll work for this build?

Thanks!
black02-z28 is offline  
Reply With Quote
Old 04-16-2018, 09:59 PM
  #2  
11 Second Club
iTrader: (2)
 
A.R. Shale Targa's Avatar
 
Join Date: Feb 2011
Location: Fredonia,WI
Posts: 3,676
Default

Thatís a good combination right there
A.R. Shale Targa is offline  
Reply With Quote
Old 04-16-2018, 10:47 PM
  #3  
Launching!
iTrader: (3)
 
ColeGTO's Avatar
 
Join Date: Jan 2007
Location: Simi Valley, CA
Posts: 202
Default

You'll want to check the chamber on the head before you order a gasket to make sure there is no gasket hanging into the chamber if it's larger than the bore.

Best way is to put Dykem on the deck of the head then put the bare head on the bare block and from underneath, lightly scribe the bore on the deck of the head. You can also reach up inside and feel if the chamber is larger than the bore.

Then place a stock gasket on the deck and see where it sits. The gasket bore should be at least .005" larger than the chamber or head whichever is the bigger of the two.

Also, you can have Cometic make a gasket with whatever bore size you want. They may even have a "standard" part number for it that Summit or Jegs carries, but may not have it listed on their site/catalog.
ColeGTO is offline  
Reply With Quote
Old 04-16-2018, 11:12 PM
  #4  
TECH Fanatic
iTrader: (7)
 
Join Date: Apr 2013
Location: S.A., TX
Posts: 1,650
Default

Originally Posted by black02-z28 View Post
Looking for a double check here, I have a 417 LS3, 4.075 bore, 4.0" stroke. Pistons are -10cc dished.

Advanced Induction has finished up my heads, 280cc with a 75cc chamber.

I want to run thinner heads to keep compression up.

Cometic .040 comes in 4.100 bore, that'll work for this build?

Thanks!
Originally Posted by A.R. Shale Targa View Post
Thatís a good combination right there
Agreed! Go for it.

KW
KW Baraka is offline  
Reply With Quote
Old 04-17-2018, 01:10 AM
  #5  
Launching!
iTrader: (3)
 
ColeGTO's Avatar
 
Join Date: Jan 2007
Location: Simi Valley, CA
Posts: 202
Default

Originally Posted by KW Baraka View Post
Agreed! Go for it.

KW
I agree, he might be safe, but it doesn't hurt to double check.

The reason I stress this is because in the OP's original post, he said the chambers are 75cc's. That sounds to me like the chamber could possibly fit a larger bore than 4.075". If that's the case and the chamber is sized for a 4.125" or larger bore, then the 4.100" gasket will be hanging in the chamber by .0125" or more per side.

Probably not a huge deal, but I wouldn't want to chance it.

If the chamber is smaller than the bore, the he could go the other way and run an even smaller gasket and gain as much compression as possible while also reducing the "crevice volume" and help emissions and knock sensitivity.
ColeGTO is offline  
Reply With Quote
Old 04-17-2018, 08:26 AM
  #6  
11 Second Club
Thread Starter
iTrader: (8)
 
black02-z28's Avatar
 
Join Date: Nov 2003
Location: Nashville, TN
Posts: 498
Default

Thanks all - good information, I will contact advanced induction and see what they advise too.
black02-z28 is offline  
Reply With Quote

Thread Tools
Search this Thread

Archive Advertising Cookie Policy Privacy Statement Terms of Service

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: