Offshoreonly.com - 1989 454 MAG Carb No Spark

I've had issues with intermittent spark for the last year or so. I never found the problem it usually healed up as quick as it came. If the boat sat a week and I went to start it no spark. I'd wiggle wires and unplug and plug stuff in and sometimes do nothing and it would start after awhile. I could never pinpoint what I did if anything. Once it started it was good for the day no matter how many times you shut it off and restarted, hit waves, wiggled stuff around, etc. Then I'd let it sit and no spark again. This time however I can't get spark back so its time to figure it out. The plug from the boat harness to the motor is long gone before I got it the wires have been spliced and shrink wrapped I've looked at those and that doesn't seem to be it. I've checked all grounds that doesn't seem to be it. I pulled the coil wire off the distributor and grounded it to the block and no spark. Can someone tell me where to start with a test light and/or ohm meter? I should have power to one side of the coil with the key on right? Thanks.