A few possible problems:
1. The 2 wires from the coil pickup may be reversed. TrailBeast gave a wiring diagram, but I don't know what all is out there in wiring. I have heard it will run with the wrong polarity, but the timing will be very erratic and it will be firing when the rotor is not aligned well with the proper post. If easy, try reversing the pickup wires.
2. You may have the wrong "double bullet" connector in your distributor wiring. If you used a general purpose one, meant for appliances, it won't make a good connection. The Mopar ones have a longer male terminal. I found this when hooking up my HEI, with a new distributor pickup (from rockauto, bought 2) and found it erratic, then saw that 1 of the 2 pickups had a regular, non-Mopar connector (Chinese factory goof? if so, how many bad ones got out!).
3. The gap on the distributor pickup is touchy. Spec is 8 mils, using a brass feeler gage. The smallest you can make the gap without crashing into the teeth (as vacuum advance moves things) is best.
4. If you totally give up, and have a small block, a new "ready-to-run" HEI distributor is only $45 on ebay. The pickups look better to me, with multiple gaps for averaging if the rotor wobbles.
