This might be completely out on the fields, based on some drawings of the GW head and the fav gulf bracket drawing.
With the "gulf" bracket the alternator is really low in the chassis. I guess they used a physically small alternator that probably sat rotated 90 deg ccw compared to this picture.
One "can of worms" here is the offset for the alternator. I got some dimensions from a unmachined casting;
The casting measures 2 5/8" between the lugs for the alternator. From what I found all ford alternators are 3" wide on this mount.
Now the original cast bracket has a bit of offset while the "gulf" bracket only got 1/2" from the head face to the back of the alternator mount lug.
Seems to be 2" on the cast one, which could correspond to replacing the waterpump with a shorty pump which is about 1,5" shorter (i think) and that was done on the gurney engines.
Not 100% sure what the below engine consist of in terms of crank pulley etc (a scan from bremar)
It has got a multirib pulley, the alternator is a from a 90's 5.0 engine.
With 1/2" from the head to the back of the mountinglug it seems to be in line with the crank pulley.
Any input appreciated.
If it turns out ok i can make some sketches and upload here so you guys have something to start with for brackets.