Found some additional history on the car today while talking with John Downing, legendary Ford Super Stock/Pro Stock racer.
Story goes, Downing saw the car in Jack Roush's shop, asked about it and what Jack was doing with it. Jack said "nothing", so Downing asked if it was for sale. Downing bought the car, told Jack to have it painted white with blue stripes (one of Downing's favorite paint schemes) and ...ready in 10 days. Then, had it picked up and shipped to Russell Hobson for his birthday in 1978 or '79, he wasn't sure of the year, to Satellite Beach, FL.
That certainly fills in some blanks between Ruggirello and when it left Detroit for Florida. Now if I can fill in the last gap in ownership around 1995 when it left Florida for Indiana, then we'll have the entire history.