There are way better cams than the 303 cams. Even a basic TFS1 cam will do better. With GT40s there are two specific OTS cams designed to be used with them. The Crane 2030 for cars with 1.6 ratio rockers and the 2031 for 1.7s.
E cam does sound badass though, true muscle car rumble with that one but depending on your year it can give the computer fits. With a carbed car though this will not be an issue.
2000 Mustang GT Steeda #0048
Just because I give you advice, doesn't mean I know more than you. Its just means I've done more stupid ****.