Actually, there is light that can be gained from the serial, it is possible it may fall into the single digit denomination era, but the date will still be there.
Further, it's the Series 80 'Pre-Run' a group of series 70 MKIV engines with series 80's stickers, which was an advertising decision, not a technical one.
I'm guessing it will show to be about 1979.
A clean up, a little adjustment, and you might just pull 100 or so on ebay as an "in use" mower.
What is the serial?
