I have the Picco and Skyward .40 engines. They are my favorite .40 size engines and I have 23. Internal parts are the same other than the cylinder liner. The Skyward porting is a little milder but they carburate well and run strong. Skyward parts are available from Udisco in Canada.
https://udisco.com/product-list.php?mid=349
They used to sell the engines but only have left over NOS stock now.
Max