Magnum 360 brackets questions

Being aftermarket brackets, they may not LOOK identical to the factory ones, the main thing is that they locate the engine correctly. It appears in your pictures that the squarish one is pass. side already modified/made with a fourth bolt hole, and the other is driver's side.
One thing I would definitely do, after final mockup; is finish welding those brackets- it looks like they're just tacked in the corners. That'll never fly.
You are the man. Thank you. I thought they were other way around so thanks for confirming the sides. I understand now the location of each. My friend did just tack them. We will go forward. Thanks again.