Ok Matt,
I think I uploaded the photos successfully.
I did a little more research and discovered that the YS classic fits the Hyde 91-115 mount with the same slight interference fit. Hmmm; so I got out some engines (a Hanno, A YS .61 LS and a YS .61AR) and
did some measuring. I discovered that the mounting lugs on the Classic are 1mm wider than the LS or the AR and 1.5mm wider than the Hanno. The mounting lugs on the LS and AR have been machined square, but the lugs on the Classic have not been 'trimmed'. My guess is that YS skipped that operation to save a little bit of $$ when making the Classic. I would be curious to know if the YS 60SR (their current hell engine in that displacement) has the lugs machined. It appears that they are in their promotional photo.
The Hanno fits the 40-80 adjustable Hyde mount perfectly as do the LS and AR...
-Will