I found these 2 bolts in a box of old hardware. The look like the 1912 to early 1913 hood shelf bolts, but I cant find any reference to the sizes in my 13 parts book.
The head is about .61 or close to 5/8s. 1/4-20 thread, with the threaded end about .80 inches long.
One bolt is 4.25" and the other is 3.75"
If they are, anyone got the other two?
The shorter one is close in length to the "long" style (rear) hood block bolt that was used in late '13 and '14 (total length with head 3-13/16"), but the slot was removed at the time that the revised (much longer) bolt was first drawn, in June of '13. Another difference is that the "long" style bolt had a crowned shank end and a hole for a cotter pin, while the "short" (front) bolt (total length with head 3-7/16") didn't have the hole.
So I would say No; these are not the Ford hood block bolts.
I thought they went through the top and bottom of the frame, so checked them on a frame and they worked.
Then I remembered just a few minutes ago, I may have pics of these bolts from Bob McDaniel's early 13. So I checked, and sure enough I did get some!
so they only go through the top of the frame.
Well, I seemed to have answered my own question! hahaha!
You could have cleaned the dirt off before you posted pics!
The heads on your bolts are the correct 5/8" diameter, and the thread is also correct. But the lengths are 3-13/16" for the rear, and 3-7/16" for the front. The bolts go through the wooden hood blocks, the top of the frame, the bottom of the frame, and the engine pans. They are held by a square nut and, in the front bolt, a cotter pin.
I should also have mentioned that the short bolt in your second photo was used until late (about June) '13. The short ones DID use the screwdriver slot. So essentially the long, non-slotted carriage bolt style is a '14 bolt that appeared at the tail end of the '13 model year.