1965 Chevrolet C10 under dash speaker installation?

Hiya folks, anyone know the steps for mounting the under dash speaker in a 1965 Chevrolet C10 truck?

I've read I will probably have to remove the wiper motor, never done that on this truck, so any tips there?

I have tried to wiggle it around under there, but no luck yet.

So, suggestions/tips/photos welcome.

Thanks.

-Woog