I have a 351C 4V with filled intake ports. I have been debating the idea of filling the ports on my x-celerator or buying an intake with the raised ports. A friend of mine is into modifying boat motors for racing. We have been thinking of building a sheet metal intake for my engine. I have a pretty good idea of what I want to do, and how I want to do it. I am just looking for advice on the do's and don'ts of sheet metal intake building. I do not have access to a flow bench, but I figure if I can keep everything the same it should be ok. Thanks.