I believe this is the bracket. Not for sale, just posting pics. If I’m wrong about the bracket please let me know.
Wierd, my 69 Riv doesn't have that bracket? Or maybe at some point the PO's never put it back on when they did the engine rebuild?
This Delco starter I have from a ‘64 300 has it. I can’t say for the 350 engines. I also have a “non-Delco” starter from a Buick 340 and the case has no provisions to bolt the bracket to it. My guess is it was used in A bodies and B bodies and probably whatever bodies. I don’t know all the bodies by letter LOL.
It ties the top of the starter to the side of the block and helps stabilize it. Think 3 pointing. Two bolts at the back of the starter and the brace. Give me a minute. I can put mine on the block, but I have a mini-starter, so it will not be connected, but you will be able to get the idea, of how it attaches.
John, your car would have had the bracket new. It stops the starter from twisting and maybe breaking the nose. It allows more solid mounting, and a better or backup ground path. As Martha Stewart would say, "It's a good thing". People toss them because they don't have the tools, or patience, or time to replace them. The bad news is, you have to have the right starter to use it. A Buick starter has a tapped hole in it for the bolt for the bracket. You can see in Brian's pic above, that there is a long threaded stud sicking out the end of the starter. That stud is for like a Chevy type of bracket. If your starter was ever changed, it may have a POC type of case w/o the threaded hole. BEfore you worry about the bracket, you need to see if your starter has the threaded hole.
Interesting, I did not know that about the stud on the front of the starter. The starter in my pic has the stud and a threaded hole for the bracket.
Brian, Buick starters typically have just 2 regular bolts holding the case to the nose. Like the one Michael posted above. But if they go to a mass rebuilder, then anything goes. That's how cases get mixed. It's the same with carbs, etc. That's how one part can have many mixed parts on it. But the stud doesn't really hurt anything.