If you click on the highlighted text next to the pic under the dual quad 427 manifold pic, you can open a larger image in iBooks that appears to be slightly higher resolution. I don't know how to tell image size on an iPad like I can on a PC.
EDIT; Now that I am on a PC, I see that last download is a PDF. I used to have a PDF to Jpeg converter, but can't find it. The PDF does appear to be slightly higer resolotion. It is too many 1's and 0"s to load directly here. I suggest downloading and saving to your hard Drive.