Flexplate and TC for a BluePrint 408 Magnum
Where is your go to place for a converter?
Personally I like Yank torque converters out of Akron ohio. They are owned by gearstar transmissions. They are 100% custom, and will build one specific to the car.
High-Performance Transmissions, Custom-Built - Gearstar
Yank Custom Built Racing & Performance Torque Converters
If you are looking to save some cost on a more "off the shelf" offering. Hughes is decent also.
But I can't say enough for a fully custom, built to order, converter, from a company like gearstar/Yank.
I put our iron headed engine in a dart years back, and with a cheap B&M converter, and the car barely ran 14's. I then had a custom converter built, and it ran 12.20's with ZERO other changes. A good converter vs one that is "close" and off the shelf, can be that big of a difference. My example is extreme, but shows a good example of one mismatched, vs custom.