I have nothing but the Green Books for part numbers.
Part number for the ramped holder? Probably lost to history.
Or Victa may just have regarded the change as a supersession, and used the same part number for both versions.
There was no provision in Victa's part numbering system at that time, for designating such changes during production. That came much later [1970's], with the XXnnnnnX format part numbers, e.g cutting blade 9-150 became CA09150S - the letter suffix can be used to express supersessions, and I believe that's its function. Edit: or one of its functions - the 'S' suffix denotes a skin packed pair of blades.
For comparison, Honda motorcycle part numbers always included both the model the part was first used on, and the supersession.
E.g. in P/No. 22870-MG7-000 the first 5 number group describes the part type [in this case, clutch cable]; the second 3 character group is the bike model designation [XLV750R]; the third 3 character group is used for supersessions, paint colours etc. For items specific to exports to a particular country, Honda uses a further letter suffix [U for Australia], but only on those specific part numbers.
Here is an extract from a late 1950s maintenance guide. 9B.
[Nice way of removing the disc nut]
That would work OK with the 9B carrier [remember, the brazed in bushes protrude a long way above the disc], but even then, I'd prefer to use a square shank screwdriver!
The other traditional method, that of hitting the spanner with a hammer, would be less likely to cause the cracks often seen around the bushes, I'd reckon. This cracking would be another reason for most 9B's having been changed out for 9C's, when these were everyday working mowers.
Good pic of the 9C Green Book page Jack; it shows the difference between the thrower blade types very well.
