CHI 4V Aluminum heads - New Bare Heads

joules"Racing is Life, anything before or after is just waiting" - Steve McQueen

I have a pair of CHI 4V aluminum heads with the larger 1.71 exhaust valve size for sale. These flow 325cfm @ 0.6 lift, only slightly less than CHI's 3V heads but allow you to use 4V intake manifolds. They accept any 351C valvetrain components and your existing headers etc.

I purchased these to use with a Weber IR manifold, but I have since sold the Webers and the project has taken a different direction as I picked up a complete crate stroker engine with A3 heads.

These are bare heads as shipped from CHI Australia and in the original boxes. Asking $1550 for the pair inclusive of shipping in the lower 48.

11/14/088:04 AM

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panteradougMember

Interesting flow numbers. That is about what the A3 heads flow.

11/15/086:14 AM

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comp2Member

The 4V for some reason are more restrictive around the valve guides. There is more material the way they are cast. They can be opened up around the valve guides to actually flow more.

11/15/086:43 AM

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72panterasteveMember

Do the CHI 3V heads work with Halls Weber intake manifold and Big Bore headers?

11/15/088:37 AM

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joules"Racing is Life, anything before or after is just waiting" - Steve McQueen

quote:
Do the CHI 3V heads work with Halls Weber intake manifold and Big Bore headers?

The 3V's should work with your existing headers although they do have a raised exhaust port. The Hall Weber manifold will not work (this is why I went 4V), in fact I think there are only 2 or 3 choices for intakle manifolds with the 3V; CHI's own and the Blue Thunder I think fit.

The 4V flow sufficient for most street engines and support up to about 550HP out the box. Any more than that and the Webers are going to be the restriction top end anyway.

11/15/0812:03 PM

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panteradougMember

Julian. Just adding information, hopefully useful. Not intending to contradict. There are two Hall Weber manifolds. One is for the standard 4v iron C heads the other is for the Raised port aluminum heads. The later is what I am using with my A3 heads.

The first one, the one intended for the iron heads will not work with the raised port heads because of the mismatch on the floor of the ports. No guys, I don't have pictures. Sorry.

I never thought to document any of this stuff.

11/15/082:00 PM

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joules"Racing is Life, anything before or after is just waiting" - Steve McQueen

Doug, good clarification, the Hall Weber manifold I have is the std 4V.

So will the raised port IR manifold work with the CHI 3V heads? My understanding was that it would not for some reason (do they differ from std raised port heads like the A3, C302B's etc.) and hence the 3V's were very limited on intake manifold choice?

11/15/083:31 PM

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panteradougMember

Joules, the way to determine that would be to overlay the intake manifold gaskets for the heads in question.

I'll attach the picture I posed before of the A3 gasket, the 2v iron gasket and the 351w gaskets here. A picture is worth a thousand words, or more.

I do not have the gaskets for the Chi heads. Do they have their own unique gaskets?

I would think that the bolt pattern on the intakes would be the same as all C family heads.

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11/15/084:02 PM

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panteradougMember

Also, what I saw in the pictures of the CHI heads they look like TO ME that they copied the Ford Motorsport heads. Now I didn't say that they didn't improve them. This isn't an accusation BUT when you guys start up about the Chinese copies of the CHI heads on Ebay take into consideration where the CHI heads came from and exactly who is copying who.

Anyway, I think that the CHI heads will work where the Ford Motorsport heads, the A3, B351, C302 heads will is what I am trying to say.