is it not on the sticker on the underside of the bonnet? i cant remember if it is mayb not
haynes manual says:
1979-1980....12degrees BTDC at 800rpm with vacuum lines connected
1981....8degrees BTDC at 800rpm with teh vacuum lines disconnected and plugged
1982.....8degrees BTDC at 650rpm with teh vacuum lines disconnected and plugged
1983-1986.....10degrees BTDC at 650rpm
i think the US 1981 supra had the 5me so i guess its 8degrees then