Ive heard that the cinquecento 700 engine was run in reverse compared to the 126 bis so they could fit it at the other end of the car and ensure it still had 4 forward facing gears!
Does anyone know if the panda 30 engine ran in reverse or if the gearbox was modified instead?

The Panda30 engine runs in the opposite direction to the 500 (110) and 126 (126A/126A1) engines. I expect if somebody was prepared to spend a LOT of money and time it might be able to fit it into a 500, but this might also involve gearbox bell-housing changes.
This is not the first time that Fiat have made what look like very similar engines run in opposite directions---the fiat 600/600D and 850 engines look very similar and in fact will bolt on the the same gearbox, BUT, they run in opposite directions. It is however,easier to make a 850 engine run backwards (or, as 1 poor guy who had not been told of this situation, found that he had 4 reverse gears and only 1 forward gear) than to make the Panda30 engine run in the opposite direction or be matched to the 500 or 126 gearboxes

Thanks for the clarification.
To expand on this (which is the main reason I was asking) I had assumed that the panda 30 and Cinquecento 700 engines ran in reverse to allow the engines to be moved to the front of the car and still use the standard gearbox.
To move the engine to the front of the car - you either have to reverse the engine, or reverse the gearbox.


So does anyone know why the main shaft for the Cinquecento 700 and panda 30 gearboxes have a reverse helical when compared to the 126/500?
I've spun one of the images round to correct the orientation and labelled them too.


I'll admit, gearboxes are not something I've really dealt with so maybe I've overlooked something really obvious!