Success!!! The gas tank is out.
Sat at our monthly Porsche breakfast, someone said they had an impact wrench I could borrow. So I stopped by his house. Unfortunately, it was the same kind of tool I had - you put a bit in it and strike it with a hammer and it twists. However, he had a larger straight screwdriver bit than mine, so maybe it would provide more torque on the bolt. While it fit the slot in the bolt better, it didn't budge it even when striking it with a BFH (I was avoiding using a BFH in case I missed or the face slipped on the wrench). Dang!
But I got an idea. I built a concoction of of bits that would end up on the end of my mom's impact wrench (well it's really my dad's but he's been gone for 33 yrs). I put the screwdriver bit into a 5/16 socket, added a 1/4 to 3/8 socket, then a 3/8 extension, and finally a 3/8 to 1/2 drive socket. Stuck it on the impact wrench, put it on the bolt, and let her rip. 4 sec later it was spun off and free! Hallelujah!!!
Took a little more work to get the tank completely out, but it's on the ground.
