If anyone is interested, the HEI I have is the last that Tom Langdon had and he is not going to make any additional units. That HEI is slated for my son's 261 motor. But I did take my Langdon HEI up to Pat Mason at Mason Racing Ignitions in Ottsville, PA to see if Pat could recreate these units. Pat is an absolute wiz with ignition systems, and was Vertex Magneto's chief engineer for many years until Vertex was sold to Taylor Wire. He rebuilds and restores all kinds of ignition systems. He just redid a magneto for me. He looked at the unit and sorted out the parts, and the modifications to the shaft. If you want a decent GM based HEI, you might consider calling Pat and talk to him about making you one.
https://masonracingignitions.com/
