Before you cut anything out My recommendation would be to make a detailed diagram & note measurements as well as cross measurements. These measurements will help determine if the car is currently strait & square, or if adjustments need to be made. ASSUMING everything is where is should be they will help you get the new parts in the correct position.
69 & 70 are the same dimensions. Measurement "H", in the diagram below is correct, however, they are measuring from the incorrect hole, it should be the hole in front of the tunnel brace. I would also measure the distance between the top of the aprons in multiple identifiable locations, inside bend NOT the holes. Then cross measure from the firewall to the front of the apron.