aftermarket valve cover
 

I got nice taller valve cover that already powdercoat. But I need to drill out to put bungs for oil catch can fitting. But I don't want something weld bung cause already painted. Is there any bung have tap thread inside hole of valve cover. I cant find it. Need -10an

10an to NPT

Google npt tap drill chart

No, for a 3/8npt, you will need a 3/8" npt tap and 9/16" drill.

I snagged two of these guys. No tap required.

https://www.jegs.com/i/JEGS/555/52230/10002/-1

The standard for Nominal Pipe Size (often abbreviated NPS, which should not be confused with the symbol NPS for the straight thread form standard) is loosely related to the inside diameter of Schedule 40 series of sizes. Because of the pipe wall thickness of Schedule pipe, the actual diameter of the NPT threads is larger than the Nominal Pipe Size outside diameter, and considerably so for small sizes. Pipe of a given size in a different Schedule than Schedule 40 provides a different wall thickness, while maintaining the same outside diameter and thread profile as Schedule 40.

I love when you give the guy the info he needs because he didnt want to look it up, then he calls you wrong hahaha.

I wonder if he knows drills come in decimal, fractional, wire gauge, metric, left hand, single flute, center cutting/face cutting, 118°, 135°: etc. I mean the list is miles long, but lets not forget, he thinks youre wrong ahahaha

Sorry, shit cracks me up.