Per my notes, the AMK tie bolt (listed as 378683-S, AMK p/n B-10222) is too short to work, at least on a 66 HP. That's before you do any grinding. The head style that was on your car is correct. I would be tempted to go to a local auto parts and brouse.
Keep in mind that AMK used best information available at the time, the Ford Car Parts book, to determine their hardware lists. The Ford Car Parts book lists service replacements parts, and not always factory originals, hardware included.
Jim