have you tried placing it in a table
72px = 1 inch
and you want information to not occupy the top or bottom 72px but the other 648px is then usuable
so
<table>
<tr height="72">
<td> </td>
</tr>
<tr height="648">
<td>CONTENT</td>
</tr>
<tr height="72">
<td> </td>
</tr>
</table>
of course, dynamic content may use more space, i would reccoment using something like acrobat which can creat header info and footer info for each page and split content accordingly (though it will place tables on 2 pages if it doesnt fit properly where placed)