I think the name you have is Alex Tremulis, but I've PM you some info on Egan
Actually Tremulis did do a proposal entitled Tucker Talisman but it wasn't this car.
Although Egan did work on the puzzle car he used as a basis someone else's work, and although you are correct in naming Philip Egan I really need the name of the guy who originated the design.
Locked for you to see what you can find!