From a Mac Pro to an iMac? Good luck with that...yes you can with another logicboard , ideally get the whole internals of a macpro and shoehorn them inside the g5 case ...
so not a option unless you really want to keep this case and have some money to waste
From a Mac Pro to an iMac? Good luck with that...
dont know if it makes the task easier if he is choosing the internals of a intel iMac , i think the easiest option and physically not that demanding would be to use the internals of a intel mini ..but it would be easier to buy a used intel imac and selling the g5