Not sure what you're thinking, but the inner bearing on J55 is different (larger) Set 5 (1.375" ID), while all cars with ABS (JM4/JA9/JB9 - B & D) use Set 6 (1.250" ID).
The spindle length & bearing spread (distance between inner & outer races) has not been validated to confirm whether they are the same, nor has the rotor plane (1.28" vs 1.04" thickness) been evaluated to see how much it shifts laterally, if any (in relation to the knuckle and caliper abutment) due to the change in thickness.
Bottom line, unless there is a way around the difference in inboard bearing size, I'm not sure there's a reliable way to do what you seem to be contemplating--even if the spindle pin length and bearing spread are acceptable.
I considered this route when I was looking at ways to do larger (thicker) front brake rotors and ended up with HD12. I was not comfortable with the idea of what would need to be done to fit the larger bearing on the ABS knuckle/spindle, so I never pursued it any further. On top of that, all effort to find a conversion bearing came up dry.
yeah i checked the spacing between the races on the j55 rotor campared to the caprice rotor and the j55 rotor races are .5 inch further apart. i was think if the spacing was the same that i could sleeve the spindle to accept the 1.375 bearing but i guess not.