318 to 360 conversion

I am converting my 68 barracuda to a 360 motor with a 904 trans. In doing so I understand that the 360 motor (1974) is externally balanced and therefore requires a 904 transmission to use a externally balanced torque converter. With this in mind found the B&M flexplate #10239 on line at Summitt racing. I called the tech support and the tech mentioned that I use this flexplate with an externally balanced torque converter. The dilemma is I have read on line including in this forum that the B&M fleplate #10239 eliminates the need of the externally balanced torque converter. So My question is with this flex plate what type of torque converter do I need to purchase?

Thank you!