GM-HEI Modules

[bamcknig at postoffice.syspac.com]

Shannen

Some time ago there was some interest in using the later HEI(High 
Energy Ignition) modules as a way to control the timing.  If there is 
a pin on the module that could be shorted out or maybe a variable 
resistor, or a variable voltage applied to, a person could control 
the amount of advance or retard from the cockpit much simpler than 
trying to run a mechanical link to the distributor. 

So I guess my question is.  What pins on what modules do we do what 
to?
Bob McKnight