Adding an oil pressure gauge

[lawnboy1200]

I have an 89 pickup with the 22re with just the basic gauge cluster (water temp, speed, fuel) and i was thinking about adding an oil pressure gauge to replace the oil light in the dash. I know there is a sending unit under the oil filter on the side of the block; what would i need to put in the hole where the sending unit is now? Is there a special thread size, adapter, etc. needed to add the gauge? Thanks in advance!!

[texas12]

There is a oil pressure switch there right now. You will need to install a oil pressure sending unit but it has to be matched to the guage you are going to use. If you do a cluster swap, then you use a Toyota (nippon denso) sender. If you buy an aftermarket guage, you need to get the appropiate sender. Should be standard pipe thread but I do not know the exact size.