I'm going to take this as my fault. I really shouldn't be postin at night when IÆm tired....
Series means the voltage is multiplied and the amperage the same per load, parallel means the voltage stays the same and amperage multiplied.

SOOO... if you rig lights in series, the required amperage is the same and but the voltage goes up. sooo.... 12.8*8 = 96 volts. W\V=A so each bulb is 4.1666666666666666 amps SO.... 4.1666*120=499.99999999

you can add/multiply powers like 50*8=500.... you just gotta remember to keep your other rules straight....

Running 8 bulbs on 120 will make them run a bit high (15v)... see if you can go out and get another bulb...

Sorry bout the confusion.