When I last did the tall spindle conversion using the 1LE's I used a b-body caliper. I have since heard that they may be too wide a throw for the 1LE rotors (they worked initally but after the pad wore down some it may have had the potential not to engage the rotor). I have also heard that 70-81 F-body calipers may have a less of a width. Does anyone know the differences in throat width between the B-body & F-body calipers? do they use the same pad?

Why not look into the C5 conversion, your halfway there anyways. Also check pro-touring.com forum. Toward the bottom of the page there is a forum titled CBB-cheap big brakes. Lots of info there.

just use the stock chevelle calipers on the 1LE rotors. it puts the hose location in the correct spot.