head gasket size - ClassicOldsmobile.com

head gasket size

Old June 9th, 2018, 06:25 AM
  #1  
Registered User
Thread Starter
 
deadeyejedi's Avatar
 
Join Date: Sep 2012
Location: saratoga springs,n.y
Posts: 997
head gasket size

what size head gasket bore should i buy for my .030 over 455 build ?would like to go with cometic and part number would be helpful.i assume .030 over on the gasket as well ? i would like the .027 thickness to maintain my targeted compression ratio.
deadeyejedi is offline  
Old June 9th, 2018, 10:02 AM
  #2  
Registered User
Thread Starter
 
deadeyejedi's Avatar
 
Join Date: Sep 2012
Location: saratoga springs,n.y
Posts: 997
after doing some research i think i answered my question .cometic offers a 4.200 bore .027 thickness head gasket for the 455 olds. if my stock engine with a 4.126 bore was bored 0.030 over my new bore should now be 4.156 ?i assume going larger with a gasket bore size would be better than going smaller.
deadeyejedi is offline  
Old June 10th, 2018, 04:42 PM
  #3  
Registered User
 
Join Date: Dec 2016
Posts: 224
Originally Posted by deadeyejedi View Post
after doing some research i think i answered my question .cometic offers a 4.200 bore .027 thickness head gasket for the 455 olds. if my stock engine with a 4.126 bore was bored 0.030 over my new bore should now be 4.156 ?i assume going larger with a gasket bore size would be better than going smaller.

Correct. One thing that a lot of people don't take into account is the amount of chamfer your machine shop put on the top of the bores. Even a .030" chamfer adds .060 to the bore size when choosing a gasket. In your case you would add .060 to your bore size for a final size of 4.206" Most of the Cometic gaskets don't seal right at the id of the gasket so the 4.200 one should be ok. To be sure measure the od of the chamfer and then call Cometic and ask them to be sure. They are very decent to deal with on the phone.
BillK is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Rilmar
Big Blocks
5
July 26th, 2016 10:12 AM
harry k
Parts For Sale
2
November 21st, 2012 08:54 AM
defiant1
Small Blocks
0
March 30th, 2011 09:22 PM
dallasite21
General Discussion
2
June 20th, 2010 05:37 AM
Sixoh
Big Blocks
5
August 8th, 2006 05:11 AM


Thread Tools
Search this Thread
Quick Reply: head gasket size


Archive Advertising Cookie Policy Privacy Statement Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

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.