Final answer:
In the book 'Shiloh' by Phyllis Reynolds Naylor, Marty finds the dog Shiloh under the porch on Friday morning.
Step-by-step explanation:
While the provided excerpts do not give a direct answer to the question "Where did Marty find Shiloh on Friday morning?", the answer can be found in the book 'Shiloh' by Phyllis Reynolds Naylor. In the story, Marty finds the dog Shiloh under the porch.