the engine cover rails bolt to the rear hull with two bolts, the front part of the rails bolt to the air ducts with two bolts.
to position the ducts what i did was use the armour squares mounted on the centre bulkhead as a datum. the edge of the ducts should line up with the edge of the armoured squares. if you have the duct scoop, measure it then check you have positioned the ducts the correct distance apart. the ducts themselves actually bolt to the armour squares......
