The mystery deepens. I contacted Stanley at Beta and got the following answer.
"Our records show that your transmission is indeed a 2:1 ratio and this has me puzzled as your engine was actually ordered from us with the 2:1. Every other BV1505 for a Westsail 32 has had the 2.5:1 transmission which I had specced out as correct for the 3,000 RPM engine on the 32's when Bud and I first got together on this.The latest spec engines are higher revving so we spec a different ratio."
I can't explain why mine is different. I ordered my engine through Bud.