Change the front mount to the later type.
Not quite that easy..
What the T2 nosecone does is not just making the trans bolt up to an older car but also lowering the hockey stick considerably so it comes out in just about the right place to match up with the gear rod in the newer tunnel.
Welding in a later mount will get the trans to sit in the right place but the hockey stick will be way off. And this is where the Berg 5 trouble comes in.. I have several friends that have tried mounting one in their 50's cars and there really isn't a way to get the trans to sit right without butchering the car/tunnel. It can be done but only as a half assed solution where both the trans and the shifter mechanism sits at the wrong angle (trans low, stick high).
Mounting the Berg 5 in the correct angle will make the hockey stick way to high, aditionally the front end of the trans (where it is bigger than a standard trans) will actually hit the car.