wrong combo???

Thread Tools
 
Old 09-11-2008, 12:51 PM
  #1  
ejf
Junior Member
SHOW GUEST
Thread Starter
 
Join Date: Jul 2004
Location: bensalem pa
Posts: 4
Default wrong combo???

My 454 bbc has 11 to1 closed chamberd pistons and square port open chamberd heads (990 casting).Is this really hurting my HP or should i go after closed heads?I race this engine and turn mid 11s in a 3500# monte ss.Trying not to break the bank on a total rebuild because engine has low miles on it.Thanks gene.
ejf is offline  
Old 09-11-2008, 03:40 PM
  #2  
zipper06
Senior Member
RACING JUNKIE
 
Join Date: Jan 2006
Location: La.
Posts: 2,890
Default

IMO, you are losing atleast 2 points in the compression, with the open chamber heads. I think the easiest way out would be to change to some 13.1 open chamber pistons. i don't know how much you would pick up but i would think close to 2 to 3ths. ofcourse you would have to rebalance the engine with these changes.

JMO

Zip.
zipper06 is offline  
Old 09-12-2008, 02:26 AM
  #3  
cepx111
Senior Member
RACING JUNKIE
 
Join Date: May 2006
Posts: 2,044
Default

Originally Posted by zipper06
IMO, you are losing atleast 2 points in the compression, with the open chamber heads. I think the easiest way out would be to change to some 13.1 open chamber pistons. i don't know how much you would pick up but i would think close to 2 to 3ths. ofcourse you would have to rebalance the engine with these changes.

JMO

Zip.
I second that>
cepx111 is offline  
Old 09-12-2008, 04:11 AM
  #4  
Tod74
Senior Member
RACING JUNKIE
 
Join Date: Sep 2007
Posts: 4,137
Default

I 3rd that.
You want to keep the open chambers , they are a better head in my opinion.
Tod74 is offline  
Old 09-12-2008, 05:27 AM
  #5  
itsabird
Senior Member
RACING JUNKIE
 
Join Date: Dec 2007
Location: ohio
Posts: 816
Default

I 4th that, keep head, more compression on piston.
itsabird is offline  
Old 09-12-2008, 03:25 PM
  #6  
ejf
Junior Member
SHOW GUEST
Thread Starter
 
Join Date: Jul 2004
Location: bensalem pa
Posts: 4
Default

well i think im going to get BIG PISTONS Thanks guys.I also thought that these heads were better.
ejf is offline  
Old 09-16-2008, 04:28 AM
  #7  
badrad
Member
JOURNEYMAN
 
Join Date: May 2007
Location: San Dog
Posts: 34
Default

You have ~9:1, your set up is exactly what GM did to the '71 LS-6 454. It lost 25HP and a little more TQ.
badrad is offline  
Old 10-03-2008, 01:20 AM
  #8  
ashbros
Senior Member
RACING JUNKIE
 
Join Date: Nov 2004
Location: St. Louis, Missouri
Posts: 661
Default

Just jerk the top end off and put a set of aluminum heads on that baby. Thats easier than pulling the engine out and apart and the additional cost may weight out after you consider all the additional time you spend tearing her down.
ashbros is offline  
Old 06-12-2021, 01:56 AM
  #9  
aquilesopkarg
Junior Member
APPRENTICE
 
Join Date: Apr 2020
Posts: 21
Default

keep head, more compression on piston.








Nox Vidmate VLC

Last edited by aquilesopkarg; 06-12-2021 at 02:04 AM.
aquilesopkarg is offline  
Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -