In an attempt to fix the oil leak I made it worse. When installing the new sensor I cross threaded it into the port. Looks like I’ll be pulling it back off, welding up the port re-drilling and tapping the threads then installing everything back on the motor. Meanwhile the whole intake side of the motor is being coated in nasty black oil. 
I wouldn't weld on the cast. Drill it out to the next NTP size and run a reducer. Welding cast sucks, welding it after that much oil saturation would be difficult also.
