Small Block & Big Block Chevy Specific Mouse & Rat Motor Discussion & Conversions

23*, 18*? What's the difference?

Thread Tools
 
Search this Thread
 
Old 06-02-2005, 10:58 PM
  #1  
Teching In
Thread Starter
 
G2 Racer's Avatar
 
Join Date: Dec 2003
Location: Ontario, Canada
Posts: 35
Likes: 0
Received 0 Likes on 0 Posts
Default 23*, 18*? What's the difference?

I'm kinda new to the SBC world so when I see this when they are talking about heads I'm totally lost. Can someone explain it?

Also if building an SBC but wanting to go Fuel injected what options does one have besides an LT/LS1 engine.
Old 06-03-2005, 07:06 PM
  #2  
TECH Addict
iTrader: (22)
 
slow trap's Avatar
 
Join Date: Sep 2004
Location: tennessee
Posts: 2,639
Likes: 0
Received 0 Likes on 0 Posts

Default

an 18 * head has the valve angle less and usually adds close to 50 hp.but almost all 18* heads requires pistons designed for 18 * heads and offset lifters.i can't remember anything else right now.for fuel injection if you already have a old school sbc put on a holley commander 950 system or accell or edelbrock or fast,whatever fits your budget.i have the commander 950 mpfi in my garage i was thinking of selling but don't know yet.
Old 06-04-2005, 04:48 AM
  #3  
TECH Regular
 
CTSV05's Avatar
 
Join Date: Dec 2004
Location: Newark, Ohio
Posts: 492
Likes: 0
Received 0 Likes on 0 Posts
Default

The 18* valve angle is rolled 5*, so to make the valve "flatter" this cuts down on the shrouding effect of the combustion chamber. Also allows a straighter path from the intake to the valve, and most often is a higher int. port location too.

My AFR 220s flow 292 @ 600 - 303 @ 700 my 18*s flow 333 @ 600 - 334 @ 700

You'll typicaly see a 50 to 100 horse gain over a 23* head. But there are drawbacks, as mentioned, shaft rockers, pistons, intake, these are not cheap parts.

If I were looking for a street motor, I would stay with a good set of 23*s, you can build a 600 hp, streetable motor pretty easy, notice I said streetable, not a daily driver!!
Old 06-05-2005, 03:36 AM
  #4  
TECH Enthusiast
 
NXSLT1's Avatar
 
Join Date: Sep 2004
Location: Clarksville,Tn
Posts: 595
Likes: 0
Received 0 Likes on 0 Posts

Default

http://www.trickflow.com/articles/18degree_hp/# That tells a lil bit about them.
Old 06-10-2005, 09:13 PM
  #5  
Cuz I AM a BADMOFO
 
BADMOFO's Avatar
 
Join Date: Apr 2003
Location: Mission to Uranus
Posts: 5,000
Likes: 0
Received 0 Likes on 0 Posts

Default

Originally Posted by G2 Racer

Also if building an SBC but wanting to go Fuel injected what options does one have besides an LT/LS1 engine.
What kind of power are you looking to make??



Quick Reply: 23*, 18*? What's the difference?



All times are GMT -5. The time now is 03:55 PM.