You would need a windage tray/scraper, oil pan, pump, tank, lines, fittings, filter setup, and cooler. It would probably be at least $2000 in parts cost alone. It costs about $5000 for a small block chevy in a circle track or road race sedan and there are a ton of brands available.
I'd suggest trying to get a used setup from a competition car. Maybe someone knows of a racing class that used dry sumped M42's. Experimenting can be very expensive when the failure is in the oil system.