Magnum mounts
Looks correct to me.
The brackets mount behind the block tabs and the lip is up.
I used Gabe's trick in the Magnum swap"how-to" on the passenger side. Used a length of all- thread with washers and nuts on all sides.
Diy - Magnum Swap!!
You should be able to used all the bolts on the driver's side.
On my 66 Barracuda I had to grind some on the driver's side block to get the starter to seat correctly and had to grind some off the truck mount to clear power steering gear.