What kind of engines will fit into a VW Camper van?

I know that you can put a Porsche engine into a VW Campervan but I was wondering if there are any other engines that work (possibly more reliable?) as I am researching buying one and restoring it to take it around Europe next year?|||A Subaru engine is popular with some. Very reliable, but water cooled.|||Audi 3liter engine can fit in that, for i have one in our Family 1997 Micro bus|||if you have the money to put a porche engine in, then you should have no problem putting any type of engine in... the problem with transplants is cost. anything is possible with the correct amount of money|||Lots of different engines will physically fit. The problem is getting any of them to work properly. That can take a lot of time and money.