Might have been me, I converted the first one somewhere around 1990...Miles Reed was at Toledo around the same with Kenny of D&B with the prototypes of his D&B twin made using the Echo parts with his own machined case...His uses the same cylinder on both sides so both spark plugs are at the same angle....Time flies []
Here's the D&B..I think the carb is an SDC80, the reed was/is a 4 petal from Homelite..