Borg & Beck Pressure Plate Springs

Do you have the overcenter spring up in the pedals? That is there to help work the B&B's heavier spring pressures. I'd do that before changing the pressure plate springs.

Over-center spring install question...

This may not be of any help but from my '62 FSM is shows for V8 clutches:
Orange spring 162 lbs at 1.5"
No color spring 189 lbs at 1.5"
White spring 201 lbs at 1.5"
Red spring 236 lbs at 1.81" (This is in the /6 section so many not be a V8 PP spring.)

Also, it seems common to make small adjustments to total spring pressures by changing out just one spring in each of the 3 sets, or even to leave a spring out in each set (which is a pretty radical change). If any are left out, they need to be all symmetircaly arrangedl.