For the oil pressure sending unit behind the intake. I think it's 1/4" NPT (what does that mean btw?) since that's what thunder sells with their guages, but wanted to see if anyone here knew for sure. I'm trying to hook up a mechanical guage to check the sending unit's accuracy. Thanks.

 

NPT is National Pipe Thread. The english standard for pipe threads.

 

and the hole behind the intake is 1/8" NPT

 

Thanks Dave , can anyone else confirm? Anyone know what the one on the oil pan is, just for extra info?

 

some places also call them national pipe taper (npt) threads

 

Sounds right to me.

 

Thanks shoebox, I was hoping you'd chime in.

 

Dave knows his stuff.