The cranks are the same on the T/GT series with the exception the GT series has a different taper to accept the PEI ignition.
the cases are only different around the alternator/PEI ignition area as each of these items have differnt mount depths on the igniton end. The T series can be modified here to accept the PEI ignition. But would have to be filled and machined on the GT series to accept the standard charging and ignition system of the T series.