[Buzz]

Iconic name builders like the original Keith Craft, Shelby and Barry Rabotnick, etc. built solid and enviable reputations as Ford FE engine experts. I doubt that many Backdraft buyers will be looking at installing high-end FE series power plants. These cars are distinctly non-original in appearance and appeal more to buyers who want a vaguely Cobra-like hotrod and will be far more likely to go the modular/Coyote or small block stroker route. Costly authentic details like 427 Side Oilers and BDR's simply do not go hand in hand because that particular buyer - compared to, say, an ERA buyer - is not so interested in "originality".
To that end, Roush is an established choice as they carry name-brand recognition and perceived cachet, and are already a popular brand of choice for Backdraft buyers.

The current Craft Engines and Lykins Motorsports both have a solid legacy of building FE's, but they are also known for their Windsor stroker engines. In terms of choosing an engine builder to bring positive name recognition and cachet by association, these two definitely belong among the top three.