when you say you want to change the payouts (a) what to and (b) for what reason?
I've had earlier Bally machines with a similar motor to drive the light effects. Quite often they stopped working years before the machine was taken out of service, but the operators never bothered to replace them. The early ones you could get into; these later ones I don't know. They run such a light spin that they are often simply gummed up with dirt and a clean will start them running again. Like I said, IF you can get into it.
It would be fair to say the machine was hacked about first by Greaves and, perhaps, later as well. It really boils down to a different glass and totally different style of paying out from the original machine, first with payouts (and perhaps the coinage) changed later.
The heat from old style lighting over many years has caused the paint to flake on the payout glass. At least you can repair this to some degree but it's hit and miss. I can make replacements if you ever need them, PM me if interested.
As Bingham says, this is at the very end of the old style electro mechanicals and the start of the fully electric controlled semi mechanicals and falls at the very end of the era we cover (but it just creeps in.