Well, the siamese port cofiguration has never really been an issue until more recently, when fuel injection has been adapted to these engines, and the intake valve overlap of adjoining cylinders begins to play its part. Many very high HP engines have been built using these heads for over 30 years and have been very effecient with carburetors and reliably as well. Its just trying to figure out how to make one injector feed 2 cylinder that share the same intake port that has shown a need to try and develop other solutions, that were never really a problem otherwise.... It would be very easy to swap #2 with #5 cylinder on the cam,as a possible solution, since they are at the same position on the crankshaft at the same time for a timing swap. That might be something to consider for the fuel injection guys that still want to use the siamese head possibly. tlowe has encountered leaning conditions in his engine with fuel injection, and has found that dividing the intake port has shown to be a considerable improvement and possible remedy for this problem altogether. And quite possibly, the simplest cure for siamese port issues.
