What Engines will fit in a 1984 Toyota Supra that came with a 5M-GE engine?

I have a 1984 Toyota Supra MKII, and i want to do an engine swap with a newer stronger car so i can find aftermarket parts for it easier, right now it has the stock 5M-GE engine in it.... I was really wondering if an MKIII or MKIV engine will fit... Im open to suggestions, any engine that will fit is a good suggestion to me right now, please help, thanks.