Mine (the square brackets) are towards the rear more and are different side to side, I have original ford F.E. engine and that is the motor mount brackets. On mine he made the passenger side removable so the engine could be removed and replaced with all the hoses and dry sump pump in place. The engine is offset to passenger side also FWTW. Did you get the model of the frame he made to do all testing on with all the rest off stuff? They are not left open, they are not finished, what motor they are for would be the question. I wish I was smart enough to post pictures, the
oil filter on mine is just behind the upper cross tube, each car was different in small ways.