...

Go Back   Lateral-g Forums > Technical Discussions > LSX Conversions
User Name
Password



Reply
 
Thread Tools Display Modes
  #1  
Old 12-16-2014, 09:20 PM
edwin edwin is offline
Junior Member
 
Join Date: Dec 2014
Posts: 3
Thanks: 0
Thanked 0 Times in 0 Posts
Default ls build advise

I am currently building an 05 LS 4.8L engine to put into a 76 Camaro and I am using heads with the 243 casting # and an LS6 intake. Well last week I was given the lower portion of a supercharger off an 2010 CTS-V. Is it worth me scrapping the LS6 intake and using the supercharger instead. Is it worth the build. Any advise, opinion or guidance would be helpful. Thanks
Reply With Quote
  #2  
Old 12-17-2014, 10:31 AM
71RS/SS396's Avatar
71RS/SS396 71RS/SS396 is offline
Senior Member
 
Join Date: Jan 2009
Location: Wake Forest,NC
Posts: 870
Thanks: 1
Thanked 5 Times in 4 Posts
Default

The LSA blower manifold will not work with 243 heads. The LSA has square port heads, the 243 heads are cathedral ports.
Reply With Quote
  #3  
Old 12-18-2014, 11:53 AM
badazz81z28 badazz81z28 is offline
Senior Member
 
Join Date: Jan 2014
Posts: 333
Thanks: 0
Thanked 2 Times in 2 Posts
Default

Quote:
Originally Posted by 71RS/SS396 View Post
The LSA blower manifold will not work with 243 heads. The LSA has square port heads, the 243 heads are cathedral ports.
Not only that, you can't put the Rect port heads on a small bore engine. OP, you might want to re-evaluate the build.
Reply With Quote
  #4  
Old 12-28-2014, 12:21 PM
71455Formula's Avatar
71455Formula 71455Formula is offline
Member
 
Join Date: Oct 2014
Location: Great Falls, Montana
Posts: 40
Thanks: 0
Thanked 0 Times in 0 Posts
Default

I saw someone has the rectangle port heads for the small bore motors. Can't remember who though.
__________________
1971 LS5 Firebird Formula with a 6 speed(Finally drivable)
2013 GMC Sierra(sold)
2000 Formula Ws6 6 speed(miss her!)
Reply With Quote
  #5  
Old 12-28-2014, 01:00 PM
71RS/SS396's Avatar
71RS/SS396 71RS/SS396 is offline
Senior Member
 
Join Date: Jan 2009
Location: Wake Forest,NC
Posts: 870
Thanks: 1
Thanked 5 Times in 4 Posts
Default

Quote:
Originally Posted by 71455Formula View Post
I saw someone has the rectangle port heads for the small bore motors. Can't remember who though.
Mast did have some but I don't believe they make them anymore.
Reply With Quote
  #6  
Old 12-28-2014, 06:37 PM
Jr's Avatar
Jr Jr is offline
Senior Member
 
Join Date: Sep 2005
Location: so cal
Posts: 1,737
Thanks: 0
Thanked 0 Times in 0 Posts
Default

I read on another forum that you can fit rectangle port heads on a small bore motor if you run smaller intake valves. Understand that I read that somewhere, I have no proof that it works.
Reply With Quote
  #7  
Old 12-29-2014, 03:50 PM
badazz81z28 badazz81z28 is offline
Senior Member
 
Join Date: Jan 2014
Posts: 333
Thanks: 0
Thanked 2 Times in 2 Posts
Default

Quote:
Originally Posted by Jr View Post
I read on another forum that you can fit rectangle port heads on a small bore motor if you run smaller intake valves. Understand that I read that somewhere, I have no proof that it works.
Where would the benefit be? Massive flowing heads with little valves. You couldn't take advantage of them. I would suggest a killer set of LS1/LS2 heads.
Reply With Quote
  #8  
Old 12-29-2014, 05:40 PM
71455Formula's Avatar
71455Formula 71455Formula is offline
Member
 
Join Date: Oct 2014
Location: Great Falls, Montana
Posts: 40
Thanks: 0
Thanked 0 Times in 0 Posts
Default

Found them.

http://www.racingheadservice.com/rhs...r-ls1-ls2html/
__________________
1971 LS5 Firebird Formula with a 6 speed(Finally drivable)
2013 GMC Sierra(sold)
2000 Formula Ws6 6 speed(miss her!)
Reply With Quote
  #9  
Old 12-29-2014, 06:24 PM
jwcarguy jwcarguy is offline
Banned
 
Join Date: Jun 2007
Location: Las Vegas
Posts: 526
Thanks: 1
Thanked 6 Times in 4 Posts
Default

Quote:
Originally Posted by 71455Formula View Post

those won't work for the OP application

The common "rectangle port" heads are the ones found on LS3, L92 & L99 engines
Some people mistakenly refer to all of the rectangle port castings as "LS3" cylinder heads, that come with huge 2.165" intake valves (LS3 are hollow stem, L92, L99 are solid)

The heads that are in the RHS link are LS7 cylinder heads, for small bore 3.90" -up (LS1 5.7L-up), the 4.8L engine that the OP has is only 3.78" bore

While the LS7 heads are a rectangle port, they are a different size rectangle port as compared to "LS3" cylinder heads (see pic)

You would need to run a LS7 intake manifold with the RHS cyl. heads

hope this clears up any confusion

Jeff

Last edited by jwcarguy; 03-24-2016 at 06:04 PM.
Reply With Quote
Reply

Thread Tools
Display Modes

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

Forum Jump


All times are GMT -5. The time now is 02:52 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright Lateral-g.net