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.
