Yes you can. The area between the stringers up there is open space. The gas tank coffin will end somewhere near the front of the console.
As an exploratory move, cut a circular 5 inch hole dead center in that area, but a little forward. Then see what you have in terms of room between the stringers. You should most likely be able to get at minimum a 20 X 14 inch hatch in there.
For reference, check the 19-6 rebuilds in the rebuild section.
Best