dunno if your engine is an old one, but if it has just been rebuilt and tight,water temp and
oil pressure guages are critical to know whats going on, especially 302 windsors, they have 2 bores that run hotter than the rest because of water jacket design and they pick up in the bore if they get too hot. it happened to me, so dont run it for long untill the guages are hooked up. personally i would never start a new engine without them,no professional engine builder would either, anyway congratulations its always an exciting time to hear a fresh engine fire up for the first time. all the best with it, cheers and beers tomcat