well if it's a celica supra it will have a 6 cyl motor, either 2lt 1gge or 2.8 5mge
i would suspect compression would need to be around 140ish just make sure it doesn't have a huge variance between cylinders
they are known to be very reliable and also check the rust.. they are very common for rusting
if it's a 1gge i think they put out about 160hp and similar with the 5m (but don't quote me on that)
good luck with it
