Doug,
You should never mount a mechanical fuel gauge inside the car as it will vent gas fumes into the car,also it won't pass tech at NHRA or may void your car insurance. That said, an isolator can be mounted on the firewall or inner fender,then connects to an electrical fuel gauge inside the car.
I run a mechanical fuel gauge on the cowl infront of the windshied,most race cars put them there.
Summit racing has isolators in stock.
Good Luck,
Perry.
