I put an EI distributor from an 81 on my 73 the other day. I used the directions found in zgarage2001. Everything went fine. I tried to fire her up, turned the key, nothing, it turned over but no fire, then when I let the key go it fired right up. Kind of like it wasn't getting any juice with the key cranked all the way in the start position. What am I doing wrong?

Sounds like you are running the ballast resistor without the bypass circuit.

Ballast resistors are meant to be bypassed during cranking so the coil gets a temporary hit of 12v instead of the 7 volts that it normally runs on.

This is to counteract the voltage drop that affects all cars during cranking. Say if the voltage drops to 10v during cranking then the coil wired through a ballast resitstor will be trying to run on about 5v, so it won't generate much in the way of a spark.

Best thing to do is find out what setup the '81 car had and mimick that. At an educated guess I'd say that it didn't have a ballast resistor and used a coil designed for EI.

Hope this babble helps.