1984 Chris Craft Scorion 230: Is there a special tachometer to use with a delco EST ignition system? I just bought a replacement Teleflex/Morse tach for my boat but the paperwork says it is not for use with aftermarket electronic ignition systems, but will work with Thunderbird. The engine that was dropped in my boat before I got it (GM5.7L) came with the delco and is not OEM for a Merc260 setup. The original tach does not read correctly.
