I also got an '87 supra the other day

[suprra_girl]

depending on where you are and the availability of manual supras in your area this can be done

have you got a turbo or non turbo?

you can get either an r154 or w58 from another mk3 supra and be able to do a straight swap.. the only thing you need to do i believe is rewire the reverse light switch which is from the auto trans loom

so you need

manual gearbox from mk3 supra
pedal box
new clutch kit
and away ya go