Need help, no spark!

So here is what I have. HEI Ready to Run Distributor from TSP which I purchased from PACE Performance. I have power to it(Red wire) when key is in ON and START positions. I have power to the Tach wire(Yellow) when key is in Start position. I have checked engine
ground. I have ran a jumper to ground from the actual ground wire at the coil, which is inside the top of the distributor housing. I have cleaned(again) the distributor hold down, the bolt, and the block around the base of the distributor. I have checked for spark at the plug and on the top of the distributor. They sent me a new one because I figured it was a bad unit, but still no change. The strange thing is that it ran great when i did the initial break in on the new build, which was just a few weeks ago, and I haven't touched anything to do with the distributor since. What else can I try?