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I have a type IV /Porsche 914 engine question. I am building a large displacement type IV engine and one thing seems to be snowballing into another and I have looked into buying some upgraded heads offered by a couple of companies or have some porting work done to my heads. The question I have is this. The heads offered have larger valve choices 46/34, 48/38 and 50/48 all with stage 2 and stage 3 porting work. My question has to do with the porting work. If the heads have porting work you would think the intake manifolds would need to be match ported but I have seen no offer of match ported manifolds or talk of anyone match porting their intake manifolds. To further the question the dual Weber type conversion intake manifolds don't appear to have much if any extra wall thickness to allow them to be opened up much. Are the manifolds already larger than the intake openings on the stock heads? Can anyone shed some light on this for me?  As you can see in the picture below the intake ports on the heads have been opened up a great deal. The intake manifolds don't appear to have the room to be opened to match... or maybe they do. Anyone have any experience with this first hand? Thanks in advance. 

type 4 intakestype 4 ported heads

 

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There is a ton of meat on those type4 manifolds compared to a type1. 

My heads are ported so extreme that both the heads AND the manifolds had extra material welded on them so the ports could be widened and made bigger in all dimensions.

So, if needed, those cast aluminum manifolds can be welded and then match-ported.

 I have heavily massaged MOFOCO 044 head ports (mine are “D” shaped and taken almost to the limit) and my CB Perf. Manifolds (I run Dellorto carbs) were not port massaged at all, mostly because I didn’t order them opened up, nor did they ask what the head port dimensions were.  

Fortunately, there was a LOT of meat in the manifolds so I could grind/polish them out quite a lot.  QUITE a lot.  To start with, the manifolds were essentially the same size as stock ports on both ends, requiring a lot of grinding.   It would have been super-cool to have one of those hydraulic honing systems with the grit slurry, but I wasn’t that lucky so I ended up using a tiny Dremel and/or cable driven die grinder and just went at it.  They are not perfectly matched, but once bolted together you can’t tell from the outside, right?

 "I have heavily massaged MOFOCO 044 head ports (mine are “D” shaped and taken almost to the limit) and my CB Perf. Manifolds (I run Dellorto carbs) were not port massaged at all, mostly because I didn’t order them opened up, nor did they ask what the head port dimensions were.  

Fortunately, there was a LOT of meat in the manifolds so I could grind/polish them out quite a lot.  QUITE a lot.  To start with, the manifolds were essentially the same size as stock ports on both ends, requiring a lot of grinding.   It would have been super-cool to have one of those hydraulic honing systems with the grit slurry, but I wasn’t that lucky so I ended up using a tiny Dremel and/or cable driven die grinder and just went at it.  They are not perfectly matched, but once bolted together you can’t tell from the outside, right?"

 

The first thing I ever did as an automotive enthusiast was porting and polishing my Austin America's BMC 1275 engine's heads and manifolds with a grinding wheel and a Black and Decker drill motor .

Last edited by dlearl476

Thanks Guys. Far as welding and grinding I have had many type 1 engines with the intakes welded and ground to match the head ports. The 2276 I just sold was an example of the intakes being ported so large they had to have the extra material welded on both the head and the intakes. These were sold this way by CB. I guess I didn't word my question well. I was mostly wondering why venders are selling ported heads and not the intakes that are match ported? The issue with the type 4 heads and manifolds is the lack of sealing area if the manifolds are ground out to match the size of the cylinder head ports. I was looking for others that have actually port matched their type 4 intake manifolds.

 Gordon , it sounds like you are talking about a type 1 engine, is that correct? Below are pics of the heads and intakes on the 2276 type 1 engine I just sold. They were extensively ported. You can't see it the pics of the intake manifolds but they are welded up a ton. I guess others are doing this themselves for the type 4 applications.

Puma 2276 CB ultra mag plus cnc ported headPuma 2276 Ported ultra mag intake throat

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  • Puma 2276 CB ultra mag plus cnc ported head

Well I have the answer to my Type 4 ported head and matching intake manifold question. The venders for the heads do offer the welded up and port matched manifolds just as done with the type 1 engines. They for some reason don't list them on their websites. 

 The snowball keeps on a rolling. My engine builder just ordered a set of heads that will be built with 48/38 valve sizes and stage 2 Porting with "D" shaped intake ports and manifolds that will be port matched. This will put the engine back 3-4 weeks on the finish date but my experience with delayed gratification has paid off big on other projects, my Suby Speedster is an example. The wait was worth it. 

type 4 ported heads

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