Mike,
For plans contact Larry at JHH....also for kits.
I've built one of each, and had my hands in/on four others (2-plans, 2-kits) and unless you want to play machinist/engineer....Buy the kit!
The kit's now come pre-balanced (not a real big issue) and can be assembled in one evening.
GREAT engines, and kits, and between Larry in California and Sara in England, they have you covered for anything you can throw at them.
Have fun, you'll learn a tremendous amount!
Greg