Engine & Internal - Replacement Temperature Gauge

I have a lengthy post about a 93 honda civic overheating, but after everything i have done and tested, i have come the conclusion that the gauge is crappy...i.e. my car temp is 190 when the gauge shows slightly over halfway.....

My question - does anyone know what the cheapest (only because she is a 93) temperature gauge is that i can use to screw in where the existing temperature sensor (temperature sender) is on the block under the distributor??....or myabe what the measurements are on this piece....

thanks in advance for the help....