Looks mean nothing. 3/8" NPT is almost 5/8" true. Vortech & Procharger use 3/8 NPT. I have instructions in front of me. Hole is 1-3/4" below the lip of the oil pan & 1/2" behind the 1st bolt. Oil drain fitting is above the oil level in the pan (no pressure), it's a hose barb fitting. No oil should be draining out of yours.
It's either a -8, or -10 an male fitting in the pic from the looks of the pic. The internal dimension of the hole will dictate which of the two it is. If it's 1/2" it's -8. If it measures 5/8" it's -10. If it's 3/4" -12, and so on.
The cap can be gotten from a hardware store, but they won't call them an fittings, ( ol dude will call them flare fittings) and there'll be a slight angle difference between the sealing surfaces, but for sealing a hole like that they'll work.
The cap can be gotten from a hardware store, but they won't call them an fittings, ( ol dude will call them flare fittings) and there'll be a slight angle difference between the sealing surfaces, but for sealing a hole like that they'll work.