From the pictures, it appears your spindles are 73-76 A body, 73-74 E body.
The casting of an F, M, J, body spindle is different in where the caliper mount itself bolts to the spindle.
To my eye, those spindles don't appear to be "tall" enough in the neck area, to be off a 73 up B body car with 11 3/4 inch rotors.
Compare to my photo of 73-76 A body spindles.
