The oil pressure gauge is correct. In '51 GMC was using a full pressure oiling 228 instead of the splasher 216 Chevy was using. This truck was bought new by my wife's great grandfather, who drove it from '51 until '76 when it got parked. No reason he would have changed of the guage cluster and speedo head. I'm pretty sure the temp gauge is correct, too. My catalogs show 220 temp for the replacement, just in tan instead of brown.
David Bush
