Any particular reason you want to? The stock fan setup is quite sufficient to keep the engine in the proper operating temperature range and doesn't require trying to get a generic shroud or shroud from another style vehicle to fit.
But if you like you can't convert your fan, you have to pull it and the clutch and find an electric setup which will A: fit in the available space, B: has a shroud which will fit properly on your radiator support, and C: moves enough air to keep your engine from cooking itself.
It can be done, but I personally consider it a waste of time, effort, and money that could be spent elsewhere on your Supra.
