I drilled a hole in my intake behind the carb for a PCV valve. The oil fill tube acted to suck in clean air as the PCV sucked out gasses into the pcv port on the carb. I made a baffle below it too so it wouldn't suck oil. Edit: It was on an edelbrock performer RPM. The still have a flat boss for the fill tube, so I drilled that out for the fill tube as well as drilling behind the carb for the PCV I love these 4 doors, it's probably the only way I'll ever have a steel 32-34 Ford. Someday.