And THAT my friends is why I started this thread! I get in such a hurry sometimes that I miss things like that.
Your silver engine photo, with the gold valve covers (the shape of the valve covers is the give-away) is a polyspherical-head engine, possibly correct for the '58, and based on the early hemi bottom end. The copper engine has the distributor forward and on the passenger side, and looks like a B-series wedge, built starting in '58 and also possibly correct for the car.
Though the air cleaners are similar, they're two different, distinct engines.
If I understand you right William, either engine should be correct for the '58, and the 318 (rear distributor) would be correct for Christine?