I have the original 170 in my '66, and it has nothing like that. I'm wanting to swap up to the 200 at some point, so I'm interested to know what that is, too. Was it original? I looked in my Falcon 6 performance book and saw no mention of valvecover brackets, but they're pretty light on the bronco specifics in that text.
I haven't had a whole lot of luck here with questions about I-6. Most people here are of the mindset that a 289 is the absolute smallest engine that can move an EB. If you want answers answers about ANYTHING ford I6 related go to fordsix.com
http://www.fordsix.com/forum/index.php. It'snot as active a board as this one (especeally the bronco section), but those guys know their engines!;D