Oil sensor thread size?

What was the size of the fitting for the oil pressure sensor behind the intake. I was thinking of putting a plug there instead(since I broke the sensor). Or does anybody know where I can buy an adapter to use with my Autometer oil pressure gauge. Thanks.

Since the sensor is already broken, use the bottom half of it and tap it for a 1/8 NPT pipe thread. I've done that on both of mine.