72, 911 Starter Motor

Can anyone offer some assistance, I need to remove my starter motor, it needs rebuilding. I raised the car pretty high but looking at the location of the starter and the top allen keyed bolt it looks like its very difficult to remove. Is there a trick I don't know about or can anyone offer the solution to how to remove the top bolt and also how to put it back in once I have the new starter.

Any help is greatly appreciated.

Marco