This one appears to be very much a custom vehicle, built from scratch. The vehicle
actually had two engines installed, which were both apparently Ford 351 engines. Only the
front motor drove the wheels however, the back motor ran, but wasn't connected to
anything. Although not mentiond in the film, in the script this vehicle is referred to as
the Lone Wolf vehicle.
At some time after Mad Max 2, this vehicle found it's way onto the site of a go
cart racing place, called "Village Grand Prix", at Blacktown in Sydney's west.
Village Grand Prix, with Nick Frame at the wheel!
I'm not sure exactly when it arrived at Village Grand Prix, or when it left, but it seems at some point the vehicle was re-acquired to be used in Mad Max Beyond Thunderdome. Obviously they changed the appearance enough that most people wouldn't noticed, and it didn't seem to be given too prominent an on screen role, just in case.
Pappagallo's vehicle as used in Mad Max 3
Picture from the Melbourne motor show, 1985
Courtesy of Gordon Hayes
Thanks to Nick Frame for his help with the information on this one, along with the picture of him sitting in it of course, and also thanks to Gordon Hayes for his pictures.