I bought an Operator's manual and a Parts and Service Manual for that blower. They both cover a B2551, a 51" version as well.
In the "Snowblower Application Chart" the B/L2563 is listed as a "Kit" for the 63" Basic Blower for
B8200 tractors. According to TractorData.com that tractor can have a 540/748 PTO and/or a 1745/2416 (hydro) mid PTO or a 2600 Front PTO. The Kubota parts listing for a B8200HST-DP tractor shows two speed-change levers but it doesn't indicate if one of them is for the PTO.
Yikes! I'm more confused now. There a many adapters and kits associated with that blower for front mounting. For a front mount there is a "speed reduction assembly" shown with sprockets and chain. By using the sprocket part numbers it looks like they have 11 and 40 teeth giving a 1:3.64 ratio. From the front-mount PTO RPM of 2600 that reduces to 714 RPM.
Bottom line: I may still have to fabricate a PTO speed increaser to boost RPM to 748. Because of the three blades vs four on most blowers I suspect it needs to turn faster to prevent the chute from jamming with wet snow which is what I experienced.
I'll investigate the size and number of blades on other blowers. Unfortunately I can't find what the diameter of the 3 blade rotor is and the unit is 500km away. Does anyone have this blower close by to measure the rotor?
The specs for the blower lists the "Fan Housing" as 18" but the "Fan Width" is a 6 7/8" (whatever that means).
After typing all of that I did some more web searching and found a free on-line manual for the
B8200 tractor and it does in fact have a two speed PTO 540 and 748. Now I'm sure I'll need a speed-increaser. Once I find one or make one I'll revisit this story.