With the head's spline cage selected in the scene, click on Tools > Transform - Type In or press F12. This will open up the transformation window. Select the Select and Rotate Tool from the main toolbar. This will change the Transform Type In to Rotate Transform. Now make sure that the perspective viewport is active in 3D Studio MAX ( 3ds max ) (right click somewhere inside it). Now enter the value 90 in the Z field of the Rotate Transform window as shown in the figure, and press Enter.

This would rotate the head in the proper orientation in 3D Studio MAX ( 3ds max ). Please note that selection of the viewport decides the axis of rotation. That is why i specified you to enter Z as 90 with the perspective viewport selected, into the transform window.

In the Transform window you have two ways to perform transformations in 3D Studio MAX ( 3ds max ) - Absolute and Offset. The values you enter inside the Absolute section will be taken as the absolute value of the model's transformation, whereas the Offset transformations will be added to the current position or orientation angle of the object. For example, if you need to specify that your model turn to exactly 270 degrees in the world co-ordinate position, enter that value inside the Absolute section in 3D Studio MAX ( 3ds max ). On the other hand if you want your model to turn 270 degrees from it's current orientation (not absolutely 270 degree orientation), you can go for the Offset section. Got it?

Now use the Scale and Move tools in 3D Studio MAX ( 3ds max ) to align the head model with the body spline cage, as shown in the figure.