Dear 'fyreline', for sure you found the correct car. Pardon, it has a completely different name in the magazine, I have!!!
The name 'Clark Alexandra' (not 'Alexander') is mentioned too, but not as the builder..
..and in my source, the car isn't based on a '56 T-Bird, but another more unusual chassis..
I cannot be sure, which is the correct one of the two sources.
Please be so kind and try to find out more. I want to award you with the point, and know as frustrating it can be, if you have found the right car, and the puzzle-creator asks for other details.
'Thunderado' may be a nick-name, based on the car's appearance. As there are some other creations around, wearing this logic composite-name...
LOCKED for you