Going by the bolts on this Victa motor you would think it's from a model 3 but I've seen 300,000 to 310,000 on model 5 and 3 and a lot of the motors were rebuilt so they just put the required barrel on the crankcase to suit the mower base that was being used.
I had a look and the early models had a slightly shorter boss so the crank may be slightly different ,I see the crank numbers are different but I think a later crank and boss should fit the 2a crankcase.
It's up to the restorer if they use the correct carby ,air filter and throttle control , there's not a lot of difference looking at the parts but pricewise there's a big difference.
