I'm installing an oil pressure gauge. I haven't decided if I'm gonna keep the oil pressure switch in via teh use of a "T" or just plug my gauge right in it's place. What I want to know is, what is teh size of the fitting that the swicth plugs into. I think my Autometer gauge comes with a 1/8" NPT. Will I need an adapter (1/4" to 1/8")?