Clutch zbar frame bracket location

[Old_iron]

I replaced the original 305 V-6 in my truck with a 350 SBC. All went well, and everything bolted up fine. It is mated to the original sm465, which I left in place during the swap.

Now that I have my inner fender off I can see the situation with the z-bar a lot better. It looks like the frame bracket (that is riveted on) is much further back than on other trucks. The stud bracket that bolts to the 2 holes in the block would not help because it would actually move the stud forward from where it is right now, which is in the rear-most hole.

Do I have to grind off the rivets and move the frame bracket forward to the next hole in the frame (in photo)? I think I'll have to drill a new hole for the rear of the bracket, I dont think there is one there.