2000 Grand Prix with a 3.8L v-6 erngine won't start

I have a 2000 Pontiac Grand Prix with a 3.8L v-6 that won't start.
Originally when turning the ignition you would hear a cluncking sound
from under the engine but thats all. I thought it was the starter
solenoid and bought a new starter. After installing the new starter,
and turning the ignition key, nothing happens. I have checked the
voltage going to the starter, (goinng from the bolt the power comes in
on to the ground screw) and get 10.5 volts when trying to crank it.
Checking from the Ground screw to the bolt with wires leading to the
starter motor, I get no Voltage when trying to crand the car. Is the
new Starter bad?

Thanks

Alan