A 66 didn't come with a 318. I say that because there are some differences between the original 273 and a later 318. One of them being a hole in the block the timing cover does not have and if you don't seal it you will get a coolant leak, BTDT. I was using an 87 318, FWIW.

My 65 Cuda has manual steering so I cannot help on the brackets.

I looked in my parts manual, brackets don't look like yours, but it's a poor picture so I googled it. They don't look like what you have.

Google 1966 barracuda power steering and look at the images, I can;t seem to link them directly.