225 slant rebuild for more power

Keep your slantsix basic and stock. Don't go installing speakers, amplifiers, and rewiring add ons until you know more about the electrical capabilities and inherent weaknesses in the stock wiring. There are some people on the Slant Six Forum who know some things. I'm saying this because you are very young and might want to be tempted to add this stuff too soon. Good luck with your '64 Valiant. Nice car.