Here is a problem with doing an external feed on a 4.1L production block. Maybe mine had core shift but in boring the oil sensor hole out to accept the 3/8" NPT fitting as the external feed setup it broke through to the underside of the waterpump passage. This might be a Hot-Air and 4.1L problem or I might be unique but its worth considering when you are doing it. I'm having an adapter made that will effectively sleeve the hole and extend the passage out to be picked up by an adapter.
Just thought I'd pass this on,
Just thought I'd pass this on,
