Ballast resistor problem?

[06Daytona]

The engine cranks over fine, stumbles as it tries to start, but when I let go of the ignition it stops. I have spark and fuel, new coil, new cap.

My thoughts are either ballast resistor, or points, one or the other since the engine started fine when I pulled it from the Charger

[72 cuda]

To my memory the ballast resister could be the culprit.

there are 2 kinds 2 prong and 4 prong.

Basically the 2 prong reduces voltage to the points to keep them from burning up so quickly.
The 4 prong has two functions it allow more voltage during the start position, and reduces it when in the run position.
 
Chryco or half the guys on this list can tell you the voltages.
Either way it should be easy to check with a test light.
Mark
 

[06Daytona]

It turns out that the ballast resistor was the problem. I had a spare kicking around the garage so I hooked it up and the engine started without a problem.