I might be able to find one in a small parts yard here. I found a '78 E-series van that has a 351M that i'm going to pull the Saginaw pump and bracket off. I think it might still have the A/C bracket. I'll check tommorrow and post back up.
The 78 E150 still has the A/C bracket on there. I'm goin to go ahead and pull it with the power steering pump and brackets either later this week or early next week. Let me know if you still need the bracket and we'll work something out.