23*, 18*? What's the difference?
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Teching In
Joined: Dec 2003
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From: Ontario, Canada
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.
Also if building an SBC but wanting to go Fuel injected what options does one have besides an LT/LS1 engine.
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.
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From: Newark, Ohio
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!!
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!!
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From: Clarksville,Tn
Cuz I AM a BADMOFO
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From: Mission to Uranus
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.
