Petrol engine replaced with Diesel Turbo - what needs changing?

I'm converting a VW van with a 4-cyl petrol engine to a 6-cyl diesel turbo. The new engine fits in the compartment, and I am also using the diesel's gearbox, but what other parts will I need off of the diesel turbo doner van to get the converted van running? Fuel pump? Alternator? etc. Thanks.