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

Best port shape?

Thread Tools
 
Search this Thread
 
Old Oct 22, 2008 | 10:23 PM
  #1  
bigsticksupra's Avatar
Thread Starter
TECH Enthusiast
15 Year Member
Liked
iTrader: (3)
 
Joined: Jun 2006
Posts: 736
Likes: 11
Default Best port shape?

Do the rectangular ports on the L92 and LS7 flow better than the cathedral style ports on the LS1s? I am talking about an aftermarket casting ported head. Just in the shape alone, is the rectangular port a better design when it comes to making power than the cathedral? Thanks.
Reply
Old Oct 22, 2008 | 10:25 PM
  #2  
zachness's Avatar
Staging Lane
 
Joined: Jul 2008
Posts: 82
Likes: 0
Default

according to the book i've read triangular is the way to go.
Reply
Old Oct 22, 2008 | 10:38 PM
  #3  
THENASCAR's Avatar
TECH Apprentice
iTrader: (19)
 
Joined: Sep 2007
Posts: 356
Likes: 0
From: San Antonio
Default

i beleive ideal port design for maximum flow u oughta check the ls7 heads.... ive read some flowing over 400 cfm
Reply
Old Oct 22, 2008 | 10:42 PM
  #4  
novaflash2002's Avatar
TECH Enthusiast
iTrader: (51)
 
Joined: Jul 2008
Posts: 616
Likes: 0
From: Billings, Mt
Default

its not always the larger port that flows the most cfm makes the best power. the real question is what are you going to be using them for.
Reply
Old Oct 24, 2008 | 04:55 PM
  #5  
bigsticksupra's Avatar
Thread Starter
TECH Enthusiast
15 Year Member
Liked
iTrader: (3)
 
Joined: Jun 2006
Posts: 736
Likes: 11
Default

yes. what is the best port shape is what im looking for. retangular like the L92 and LS7 or cathedral style. Both will be an aftermarket CNC ported casting. Just looking to see what shape is ideal for maximum flow and horsepower.
Reply
Old Oct 26, 2008 | 06:27 AM
  #6  
NightTrain66's Avatar
LS1TECH Sponsor
iTrader: (7)
 
Joined: Oct 2002
Posts: 414
Likes: 1
From: Texas
Default

depends on the cubic inch and RPM you plan on shifting at.

The advantage of the L92 and LS7 head is that the pushrods are further apart and this allows a straiter shot and a larger cross section at the pushrod pinch. There is less of a velocity change at the PR pinch by doing this and these ports flow some real good #'s but you also have a pretty large runner volume and a large cross section at the pushrod pinch (minimum cross sectional area of intake port).

If you have enough cubes (408, etc) or spinning enough RPM with a smaller engine to make use of this, great, it is a better way to go.

If trying to use them on a small engine, the port ends up bing lazy and when the piston reaches BDC, there is no inertia still filling the cylinders with the big port where a smaller port would still pack a lil more in the cylinders.

A smaller engine will be better off with the LS1, LS6 style head and keeping the runner volume and push rod pinch cross section smaller.

Lloyd
Reply
Old Oct 26, 2008 | 09:09 AM
  #7  
valiant65's Avatar
On The Tree
 
Joined: Aug 2007
Posts: 112
Likes: 0
From: Finland
Default

Maximum head flow matters only on n/a applications. If going FI, pay attention more to exhaust/intake flow ratio and overall head desing (i.e. deck thickness).
Reply
Old Oct 26, 2008 | 04:33 PM
  #8  
Hi-Po's Avatar
TECH Enthusiast
iTrader: (4)
 
Joined: Nov 2005
Posts: 712
Likes: 0
From: Florida
Default

Originally Posted by NightTrain66
depends on the cubic inch and RPM you plan on shifting at.

The advantage of the L92 and LS7 head is that the pushrods are further apart and this allows a straiter shot and a larger cross section at the pushrod pinch. There is less of a velocity change at the PR pinch by doing this and these ports flow some real good #'s but you also have a pretty large runner volume and a large cross section at the pushrod pinch (minimum cross sectional area of intake port).

If you have enough cubes (408, etc) or spinning enough RPM with a smaller engine to make use of this, great, it is a better way to go.

If trying to use them on a small engine, the port ends up bing lazy and when the piston reaches BDC, there is no inertia still filling the cylinders with the big port where a smaller port would still pack a lil more in the cylinders.

A smaller engine will be better off with the LS1, LS6 style head and keeping the runner volume and push rod pinch cross section smaller.

Lloyd
Reply
LS1 Tech Stories

The Best V8 Stories One Small Block at Time

story-0

Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

 Verdad Gallardo
story-1

6 Common C5 Corvette Failures and What's Involved In Repairing Them

 Pouria Savadkouei
story-2

Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

 Verdad Gallardo
story-3

Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

 Pouria Savadkouei
story-4

Top 10 Most Powerful Chevy Trucks Ever Made!

 
story-5

Hennessey's New Supercharged Silverado ZR2 Has 700 HP

 Verdad Gallardo
story-6

Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

 Verdad Gallardo
story-7

Awesome K5 Blazer Restomod Comes With C7 Corvette Power

 Verdad Gallardo
story-8

10 Camaros You Should Never Buy

 
story-9

10 LS Engine Myths That Refuse to Die

 Verdad Gallardo
Old Oct 27, 2008 | 07:07 PM
  #9  
bigsticksupra's Avatar
Thread Starter
TECH Enthusiast
15 Year Member
Liked
iTrader: (3)
 
Joined: Jun 2006
Posts: 736
Likes: 11
Default

It is a 427 Ci LSX block with a F1R Procharger. Looking for maximum horsepower in a aftermarket six bolt CNC ported head casting. Budget is up to $4K for cylinder heads. Please advise, thanks.
Reply




All times are GMT -5. The time now is 09:51 PM.

story-0
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

Slideshow: This heavily modified 1971 Camaro mixes classic muscle car styling with a fifth-generation Camaro interior and modern LS3 power.

By Verdad Gallardo | 2026-05-12 18:06:42


VIEW MORE
story-1
6 Common C5 Corvette Failures and What's Involved In Repairing Them

Slideshow: From wobbling harmonic balancers to failed EBCMs, these are the issues that define long-term C5 ownership and what repairs typically involve.

By Pouria Savadkouei | 2026-05-07 18:44:57


VIEW MORE
story-2
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-3
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-4
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-5
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-6
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-7
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-8
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-9
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