Does it have a bolt on inlet bell or just a snout on the compressor housing? You will need to remove the downpipe and the inlet hose, take pics of each wheel and measure the hole sizes and post them up then we can tell you what you have.
Bolt on inlet bell = T/A series. take off the bell and measure the hole size, count the fins big and little ones and a pic would be nice. no way to tell without.
A ta64 would have a 66mm compressor and need a huge stall , is the car worked? is their a lot of lag? if it has few mods and spools quick its probably a ta49 or ta60...def will need pics and measurements