Stalker is a 221, very similar to the follow up to the Rom Champion book. I have a PDF of this book:
https://www.amazon.com/Build-Your-Own-S ... 1844253910The builds are often called "Haynes" builds cause the book was published by Haynes.
In this follow up book, Chris Gibbs makes corrections are made to the Champion design, plus all of the most popular modifications (ie, "Aussie mods" to strengthen rigidity, add 2", etc). By this time, Ron Champion had run into some personal difficulties and wasn't really around to follow up (or something).
And I also have the VooDoo plans if you need them.