I heard a story once that Jacko had a fight with Maurice Rioli and Maurice won.
I grew up in a Western Victorian town, Essendon zone in those days, same town that produced Roger Merrett, Glen Hawker, and later Alistair Clarkson (all champions in my eyes of course, Clarko's mum was my kindergarden teacher). Anyway, my dad owned the roadhouse there, and one night, on his way to Adelaide, Jacko pulls up in his Lamborgini (IIRC). It was probably when Adelaide still had the Grand Prix. Anyway, Jacko fuels up, walks inside and grabs a Guava juice from the fridge. Walking up to the counter, he asks my dad if the juice was any good. Without a pause, just being the guy he is - ie. no ill will involved, dad says: "it'll put hair on your head". Being sparse on top at that point, Jacko didn't take to that comment very well: "everyone's a ****ing comedian", was his unimpressed response.
Nonetheless, I've still got a picture of myself as a gangly teenager sitting in his Lamborgini. Must have been before he bought the guava juice.