Hi Gadge ,Tubes,Jack and all.

I agree with Gadge,a lot of mower repairers had change over reco motors meaning many old mowers do not
have the original engines.

A lot of people see a engine on a mower and think it's original,I look for evidence that proves
the engine is the right one for the base.

Original documents are the best way someone can prove which engine came off which base.

If you know the Victa Special model 5 series 1 ended around the 355,000 mark in 1959 then it's
not difficult to figure out the model 5 series 2 started in 1959.

Image of a sales document showing the AA prefix and the date 1959
that proves the AA prefix is correct for the model 5 series 2.
https://www.outdoorking-forum.com.au/forum/ubbthreads.php/topics/51968/8.html


I would say the IAAA prefix is off a later build of a model 5 series 3 (no edger slot on base)
Cheers ,Max.