I would also put the fly wheel in the freezer over night helps to reduce the size
But i wouldn't have a problem about heating the the ring gear with a torch just go gentle with the heat and all will be well :thumbsup:
If you heat it in one place with a torch then you will spoil it just go steady and evenly
You will find it will prob fall on if not then a length of timber that will go across the ring gear and a hammer will sort it just be quick about it as the size difference will be short lived
As said above bevel to starter:thumbsup:
Ps my wife isn't very understanding about machinery in the kitchen since she came home an found me baking a cast iron pump housing ready to weld as they are so thin that they crack otherwise