Sure it's possible.
You would need to have the necessary fabrication and electrical skills to do it. Or contracting with someone to do it, which would cost far in excess of what a '91 4Runner is worth.
IMO, it would be far cheaper and easier to just buy a 4th gen 4Runner with the 4.7 V8. Possibly adding a supercharger to that if the stock 4.7 isn't enough.