Thermo Vacuum Valve plug size?

[OldSchoolMotors]

What size plug can I put in place of the Thermo Vacuum Valve, I want to clean up the engine bay and I already have this disconnected, now I want to remove it completely.

I'm looking for the thread size of a brass plug I can use?

 

[99gst_racer]

Can you provide a picture?

I've been working on these for a while now, and I have no clue what a "thermo vacuum valve" even is.

 

[OldSchoolMotors]

I may have mispoke when I said Thermo Vacuum Valve, the link shows the piece in question

http://www.dsmtuners.com/forums/bolt-tech/258471-thermal-control-valve.html

A member replied with the 17mm x 1.5 thread as the size for this, in that link.

What size brass plug would fit that? Thanks.

 

[turbosax2]

I've used a 3/8" NPT plug in there without leaks. I'm not sure if the threads are actually NPT though.