Large Scale Central

Voltage for E-8 front lights? Anyone know?

I just got the nose and front light board from Marty for my Short E-8 project. Finishing it up, anyone have any idea of what voltage to apply to the board? All the bulbs seem to be incandescent, not LED’s. I tried 6 volts which worked, but they seemed a bit dim, but was afraid to try 9.6. Jerry