View single post by Mark Rosenbaum
 Posted: 05-10-2006 05:56 am
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Mark Rosenbaum



Joined: 03-12-2005
Location: Kingman, Arizona USA
Posts: 532
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 The 23D (no vacuum) / 25D (with vacuum) series and 43D (no vacuum) / 45D (with vacuum) series use different distributor caps.  I'm not sure about the other tuneup components (points, condenser, rotor).  The distributor casing should have the model number cast in, but if that's not visible, then the 23D/25D has a body that tapers inward a bit as it approaches the engine, and a cap that's rounded or domed; in contrast, the 43D/45D has a basically cylindrical body and cap.  I've attached a photo of a 25D distributor.

Most JHs were built with 23D/25D distributors, with only some of the later cars using the 43D/45D series.  I don't know of any factory documentation that indicates the time frame in which the transition occurred.

The cap with wires coming from the side is an older design that dates back to the 1950s if not earlier.  There's nothing wrong with this side-exit design, presuming it's made from modern plastics suitable for use in ignition systems, but in a JH, the top-exit design allows a cleaner ignition wiring layout.  Some versions of the side-exit cap use screws to hold the high voltage wires in place, rather than the arrangement where the wires just plug in.

Attachment: 25d4 view 4.jpg (Downloaded 70 times)