The 5sp part number for a 87 BJ74 model 5 speed is 33030-60500 . You could use any H55F gearbox as long as you have the correct input shaft, bellhousing, clutch etc. I don't think you will have a problem fitting the 13BT gearbox to the 3B. The BJ73 (non turbo) 3B is using the same part number .
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