depends on which GS it is. If its a mk1 jzs147 then you are better off scrapping it unless you really want the car. The mk2 jzs161 might make it more economically viable to do an engine swap.
Good source of n/a 2jzs is the supra owners club ;) and would imagine off ebay its 3-500 for a ge lump shame as i scrapped a gs with a good engine not long back
Thanks for that advice and it is the Mk1 so it's see ya later then i reckon, shame cos the rest of the car is lovely and it was fantastic to drive!!