i have owned a 87 turbo supra for 4 years now, and consider myself an expert on them, rebuilt the engine, swapped in a 1jzgte (crazy JDM engine 280 hp stock twin turbo). The 7mgte engine is prone to blowng head gaskets, make sure that the head gasket isnt blown before u drive it. Furthermore I sugguest replacing the head gasket with a metal one and ARP head studs. This is required to make these care reliable. supraforums is a good place to get more questions answered. They are great cars, but the 7mgte is not a reliable engine. Look at the 1jz section if you want to make it a real beast.
~scott