The possibilities you have: (from your avatar I'm assuming not an early A body)
67, either /6 vs V8 of course has different mounts, both 6 and 8 are "biscuit" or "pillow" mounts, and the idler arm only has one bracket, that is a one year idler arm
68--72 same as above except has upper and lower idler arm brackets, that is better design idler arm
73/ later has "spool" engine mounts, a huge improvement
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Steering box is easy: Does it have hose fittings? Is it cast iron? If yes it's power
No hose fittings and aluminum box means manual
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There is (and parts could be switched year to year) a "large spline" and "small spline" steering boxes.
NOTE!!!
The center link / idler arm / pitman arm / box all have to "match" Go here:
