Give
www.turbomustangs.com a try. They have links to all the major turbo kit manufactures as well as most of the companies that just offer turbos, plus links to build your own kit (commomly know as a JY setup). Some of those would help you determine what size turbo would work better for you. The one from the SVO will definately not be enough for you, heck, two of them would probably barely be enough. For a 351, somewhere between between a T62 and T72 would probably better suit you for a single setup. For a twin setup, some type of TO4's would work.