Is it 100% on all Catalina 36 boats with the Universal M-25XP and Hurth HBW-50, the gear ratio is 2:1?  I could not locate my transmission built tag (nor could others).

[quote=newguy]The HBW-50 "standard" transmission specification given in all M25XP documentation is 2.05:1 ratio.  Perhaps Hurth offered different ratios, perhaps Universal could and would offer these different ratios, and perhaps Catalina could and would offer these different ratios to the buying public, but it all seems to be a long shot.  Why do you think differently?[/quote]
I need to purchase a new/rebuilt transmission.  The stop attempting to replace my stuffing box for a PSS bent the transmission output flange using the exact procedure Catalina Direct cautions you NOT to do:  https://www.catalinadirect.com/index.cfm/product/3613_844/coupler-puller-yanmar--universal-diesel.cfm 
Then the shop passed the completion of the project to another shop.  My preference is to purchase the replacement transmission from Foley Engines to have it ready when the diesel is pulled.  But I can not locate the original Hurth build tag on the transmission that displays the gear ratio and Foley's will not sell me a transmission until I confirm the gear ratio.  So the will need to pull it first and confirm by spinning the input shaft.  Does anyone know of the exact location for the transmission build tag?  I looked all over with no luck.

You may want to look at replacing your 50 with the 100 ( ZF 10 M ) which is just slightly longer. I think the 50 is under spec. I did this on my C30 without any issue, just had to move the prop shaft back about a 1/2 inch.