Originally Posted by Jmark
The DUI ( Davis Unified Ignition ) distributor is very similar to a GM HEI with the exception of the pickup. The DUI uses a Hall affect trigger instead of the reluctance pickup that the stock HEI uses. Haven't hard much about them actually. Don't know how much you paid but a good working junk yard HEI probably costs 10 bucks now days.
Since I put the DUI into the car. It runs great. The problem with a stock HEI unit is that the advance curve is not correct for a '70. I had one ion there for years. The DUI went right in and cured all my problems including the pinging.