Tadream

My 86 Z28 came to me in pieces and among them, three complete instrument clusters. I have an 85, 110 and 145 speedo and the three techs with the oil pressure gauge integrated. Trying to pick the best of all, I noticed one is an 80PSI while the others are 60psi units. The engine is rebuilt, and as yet unstarted, but I've cranked it over with a mechanical.gauge installed and it has a high volume pump and the pressure was such that I'd like to use the 80psi, but that face is faded, and other discussions sound like it was only on V6 models. Is this correct? And is this likely a V6 tach also, then? I really DON'T want aftermarket gauges in it. I'd rather make sure the factory ones are working and accurate and I have to get a sending unit anyway. So, do I have any options for keeping the 80psi gauge or must I keep the 60 and ride around with it pegged most of the time?