Cam changing on an EFI motor will require a chip change in the computer. Cam has major impact on opening/closing of valves and since fuel and spark delivery is married to this opening and closing event, the computer has to initiate the event at the precise time, or it will run like a dog. An example is ordering a Edelbrock Pro Flo system: they want your cam data in order to provide you with the correct chip for the computer. After installation, the instruction manual provides additives for more cubic inches or subtraction for less cubic inches. The basic system is for a small block Chevy/Ford or big block Chevy?Ford.