Correct my last.
In the 65 Mustang Engine Equipment Assembly Manual, AM0155, pg23, the tube assembly, crankcase ventilation (C5OA-6758-A) upper bracket attaches to the rear of the right hand head with 378604-S8, bolt, 3/8-16 X 3/4 Hex Sems or 373461-S8, bolt, 3/8-16 X 3/4 Hex Sems, and 356403-S8, washer, 3/8, and a stud, 308085-(??) which is not listed, but holds the engine to the bell housing above the starter, the nut and washer are not referenced. Both brackets are "U" type, they "slip in" the bolt/stud.
Jim