At my wit's end

Pulled the dizzy this afternoon and moved it one tooth over and put a different cap on it. I turned the key and it fired right up. I tried adjusting the timing to get it right and once it idled ok I revved the engine to make sure it didn't die. Once I got it to not die while revving I decided to take it for a drive. I got it about halfway down the block when it started to stumble while holding the gas down. Eventually it died.I started it back up and it just seemed to get worse and worse. Once I got it home I tried adjusting the timing and playing with the air mixture but nothing change. Eventually it just stopped turning over. Only thing I can think of at this point is the HEI heatsink I made isn't doing its job well enough. I am going to see if it turns over again once everything cools down which would probably answer that. HEI module is out of the cheap HEI dizzy I have on my Ranchero too, so it could just be the chinese junk. Going to pick up a new proper one this weekend regardless.