Joe, what is the center to center spacing of the capacitor screw holes? I measure 3.000" on both the PL400 and the PL700B amplifiers. Of course, that depends on the rotational axis of the two capacitors and therefore the terminal screws radial linearity. Mine are at 45 degrees from vertical, plus or minus.
In other words, the Big Ass Bus Bar should work in any PL400, PL700B, PL700 II, PRO700, and the Mighty Dual 500.
Mark