Walter never did an Impact kit.. One was done by the Moon brothers, UHP, I still have it.
Walts first kit was the Super Duper Zilch, he did F5F, Spitfire, Sea Fire, Trophy Trainer, 660 Stiletto, profile Stiletto, USA 1, Volunteer, Galloping Comedian, Ringmaster Imperial, International Stunt winner, several llimited production such as the Howard Ike, and more I cannot think of yet.