There is a wesite dedicated to that F body spindle on A body. I can't recall what it is, but if you get no answers today, I will try to look when I get home from work tonight.
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1966 Strato Chief 2 door, 427 4 speed, 45,000 original miles
1966 Grande Parisienne, 396 1 of 23 factory air cars (now converted to a "factory" 4 speed)