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

408 heads/ cam ??????

Thread Tools
 
Search this Thread
 
Old May 1, 2005 | 10:22 AM
  #1  
Moralesrx7's Avatar
Thread Starter
Staging Lane
iTrader: (1)
 
Joined: Sep 2004
Posts: 54
Likes: 0
From: Lanett, AL
Default 408 heads/ cam ??????

i have a 408 being built right now should have it by the 3rd anyway i changed to the 408 in middle of building up a 346 my question is that i have p&p casting 806 5.7 heads that flow 298@600 on a std. bore one do i need to have these cnc to a 4.03 bore or will they work (im using a graphite gasket)and two these heads have a cc of 69cc ? or 66.7cc like the rest of the 5.7 heads because my cr seems to be 11.5 - 11.7 at 69cc. anything higher will be hard to run on pump gas.
i running a tsp giant cam,
ported tb,
ls6 intake,
42s inj,
jtr long tube 1 7/8 headers,
slp 85mm mafs
255 pump
ls6 port pump
and 100 dry shot
in a 93 fd rx7 w/ t56 and carbon driveshaft
thanks for any input also any ideas on rwhp would help
Reply
Old May 1, 2005 | 11:03 AM
  #2  
Richard@WCCH's Avatar
Banned
iTrader: (3)
 
Joined: May 2002
Posts: 1,853
Likes: 5
From: Van Nuys, CA
Default

Unshrouding the valves will help slightly. You'll see a minor loss in compression ratio due to the larger chambers. I'm not sure what your budget is, but upgrading to larger valves (2.08"/1.600") will help out your combination. The larger bore of the 408's accomodates the larger valves well. Trading some compression ratio for increased airflow is ok in my book when running pump gas, especially when cr is in the 11.5:1 range.

Enjoy that hot rod :-)

Richard
Reply
Old May 1, 2005 | 11:04 AM
  #3  
Demon SS's Avatar
TECH Resident
iTrader: (3)
 
Joined: Nov 2002
Posts: 824
Likes: 0
From: Pewee Valley,Ky
Default

these will work ok, but IMO the combustion chambers need to be opened up to match the bore.
Reply
Old May 1, 2005 | 11:06 AM
  #4  
2c5s's Avatar
10 Second Club
20 Year Member
iTrader: (11)
 
Joined: Sep 2003
Posts: 1,676
Likes: 0
From: Murrieta Ca.
Default

Originally Posted by Moralesrx7
i have a 408 being built right now should have it by the 3rd anyway i changed to the 408 in middle of building up a 346 my question is that i have p&p casting 806 5.7 heads that flow 298@600 on a std. bore one do i need to have these cnc to a 4.03 bore or will they work (im using a graphite gasket)and two these heads have a cc of 69cc ? or 66.7cc like the rest of the 5.7 heads because my cr seems to be 11.5 - 11.7 at 69cc. anything higher will be hard to run on pump gas.
i running a tsp giant cam,
ported tb,
ls6 intake,
42s inj,
jtr long tube 1 7/8 headers,
slp 85mm mafs
255 pump
ls6 port pump
and 100 dry shot
in a 93 fd rx7 w/ t56 and carbon driveshaft
thanks for any input also any ideas on rwhp would help
Any relief in the pistons?
Reply
Old May 1, 2005 | 11:32 AM
  #5  
Moralesrx7's Avatar
Thread Starter
Staging Lane
iTrader: (1)
 
Joined: Sep 2004
Posts: 54
Likes: 0
From: Lanett, AL
Default

2cc reliefs, so the heads have to be cnc d to a 4.03 to work and do the 806 have a 69cc chamber? i did a search and cant find a postive answer thanks
Reply
Old May 1, 2005 | 12:53 PM
  #6  
Richard@WCCH's Avatar
Banned
iTrader: (3)
 
Joined: May 2002
Posts: 1,853
Likes: 5
From: Van Nuys, CA
Default

Originally Posted by Moralesrx7
2cc reliefs, so the heads have to be cnc d to a 4.03 to work and do the 806 have a 69cc chamber? i did a search and cant find a postive answer thanks
All the stock 806's we've cc'd had a chamber volume of approx. 69cc. They'll probably grow to 71-72cc's after unshrouding.

Richard
Reply
Old May 1, 2005 | 12:57 PM
  #7  
Moralesrx7's Avatar
Thread Starter
Staging Lane
iTrader: (1)
 
Joined: Sep 2004
Posts: 54
Likes: 0
From: Lanett, AL
Default

thanks any idea on power off the juice
Reply
Old May 1, 2005 | 01:02 PM
  #8  
kumar75150's Avatar
TECH Fanatic
 
Joined: Mar 2003
Posts: 1,112
Likes: 0
From: Dallas
Default

what cam are you using?
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 May 1, 2005 | 01:16 PM
  #9  
Moralesrx7's Avatar
Thread Starter
Staging Lane
iTrader: (1)
 
Joined: Sep 2004
Posts: 54
Likes: 0
From: Lanett, AL
Default

tsp giant cam http://www.texas-speed.com/item_deta...?ProductID=186
Reply




All times are GMT -5. The time now is 02:19 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