Msd 6al box question?

I have a 347 stroker ford, it's a carbureted engine, and it has an msd 6al ignition box etc. Whenever the car has been sitting around like a cold start, it will crank right up and run fine. But when he gets hot, it will not start back up, meaning I have no spark. I have checked for spark while cold, and it's fine. I checked the msd box for spark at cold and its fine, but when the car gets hot, it doesn't have any spark. Any ideas? I just replaced my coil with a new one with a msd blaster coil. What else could it be? Iv'e checked all the wire connecections to make sure everything is tight. And it seems like the problem is just getting worse, like today, I went to go start it up, and it would keep cutting off at a cold start somewhat. The problem is getting worse. What could it be?