Your right Rob, they started life as a Proboat before I cut them & changed em. I'm in the stages of making new design hulls that would be even closer to the GP class hull, the plug I'm working on is a tri wing hull like the old gp1 spellbound. It's an auld designed hull that was made about 1998ish & raced in Australia as a twin turbo'd v8, or another version was gp5 wasp racing. It ran a ford small bock v8 before being cut up & rebuilt into its current shape. Spellboaund was destroyed in an accident & never fixed.
After that the next hull design is another auld the old gp101 that Jeff Bernard drove when it was painted in the flames