Could my 340 block be filled?

Watch your gauge while warming up with the infrared on the themostate housing, then you know what the gauge marks mean.
Well i put the new heat sending unit in and fired up the car. I let it warm up for 20 minutes. I used the infrared thermometer and hit the water neck. The temp was at about 180. I went for a ride to a friends house and the temp was at 190 and the gauge was way lower than it has been. I shut the car down for about 15 minutes or so and when I went to leave my car would not start. It was turning over but I had no spark at all. This is a problem I have also been chasing for a while. I'm thinking the coil is getting to hot and failing. It is a newer coil.....jap crap from rock auto mounted sideways on the intake like it would've been from the factory. I check the wires connected to the coil and I felt oil at the top of the coil. Oh the pain.....anyone have a recommendation on a good coil I should try. I'd like it to look and mount in the stock location.