another no start issue!!!! (more than a little frustrated)

Ok well we got it running finally. I changed to a new points distrubutor. new coil, a larger battery. dropped a bit of oil in each cyl. and off it went. I found that I need a much smaller carb. I have an 850 eldebrock. guess it is to much. here is a new question. I did not have a know good oil pressure sending unit here, so I pulled the old manual guage out of the chevy Nova, and installed in the dodge. I fired it up, and at idle it shows now oil pressure. as I rev it up it goes to 30ish warm at about 2000. this is exactly what the guage was doing in the chevy...the 400 chevy is a brand new motor all the way around, nothing left in it stock. fired it up the first time and had the same reading. I have not run it since as I bought this dodge and have not looked at the nova in months. now I install the guage in the Dart and the guage is doing the same thing. I was kinda pissed so I just let the Dart idle for about 1.5 hours. no heat, no noise, everything looks good. the guage was a cheap thing from napa. how long can an engine run with no oil pressure? I would have thought something would have gave up by now. reved it up a bunch, still no noise. Man this car is kicking my arse. then again if the guage is bad, that will make me happy with the other engine. cant believe that 2 engines, 1 built by me and 1 by a prefessional, would read the same on the guage. BTW oil level is good. there is no iron in the oil, but we both used white assembly grease in the engine. I am running 10w-30 oil in both, but am going to run Mobil Delvac 15w40 as soon as it is time to change the oil. BTW thanks all for the help, that thing really sounds good even with the stock single exhaust.