Cadillac Northstar V8 is under the valley cover. It's a PITA, but the absolute worst I've ever replaced was the Chevrolet Chevette. The 1st step is to electrically & mechanically disconnect and pull the steering column. The 2nd to the last step is assembling a 14 mm socket to a 6" extension, then while feeding this assembly through a maze starting up near the radiator, add a universal swivel, a 10" extension, and finally the ratchet to remove the top bolt holding the starter back near the firewall. Putting that top bolt back was nearly as much fun as removing it.
First starter replacement took close to 8 hours. By my 3rd, and final one (I owned several Chevettes) I had nearly cut that time in half.