The '55 case is the first year to use one large and one small drive side bearings.
Neill Singles '48-'57 says crankshaft end float 0.020"-0.025"
Neill Singles '57-'66 says crankshaft end float 0.012" minimum.
Do you think the 0.012" value is the relevant value for cases with the large/small bearings, although in this instance '55?
Or is it academic and not that important?
I have 0.016" end-float
