If your MSD box is mounted above the passenger's feet, where it is nicely hidden, then the easiest wiring method is to run the fat red wire through the firewall to the hot side of the 50 amp circuit breaker, the fat black wire should run directly to the passenger side cylinder head where you presumably have the battery's negative cable grounded. You should also be using the MSD Capacitor as it prevents a number of problems. It's called a Noise Filter but it's really just a big capacitor. Run the wires from the box to the coil down one side of the block and run the wires to the magnetic pickup down the other side of the block. This is a tried and true wiring method.
