dennis,
i bought a complete kit from performanceonline.
yes, it uses modern roller bearings that happen to be for a 1970-78 camaro, since the rotors and calipers are from the same vehicle, 70-78 camaro. the kit comes with a bearing adaptor that slides over your original spindle for the new bearings to be able to work.
i used the under floor board mount, since it was the easiest to install, bolting up in the original location, and using my original brake pedal.
yes, it is a little bit of a pain to fill with fluid, but once its full and in correct working order, you dont have to keep filling.
also, if you go with a fire wall mount, i think you have to reinforce that area with bracing, since the factory fire wall is not strong enough for the brake pedal pressure you will be applying.
someone correct me if i am wrong on that, but i believe i seen in an article that you have to reinforce the fire wall.
hope this helps dennis.
leonard