I have the same setup Watch where you mounted the MSD The main weakness of the MSD is MOISTURE and heat: If it gets wet or moist, the MSD will die on you. I have mine mounted on a fabbed plate, mounted just behind the battery toward the firewall, it sits face up, almost at the height of the battery
FP gauge is mounted just like yours. Brain box is mounted inside, below dash, to the left of the steering column
Dont know if you have the same, but I am using the OEM gas tank, wit no sump or baffles. If I get just low on fuel to just above 1/8 tank, I have noticed the pump will run dry, so run at least 1/4 tank at all times