Looking for the mechanical advance specs for this distributor. They are normally in the "Owners Manual" and list the degrees advance with the corresponding distributor RPM's. Trying to find out how they match up with the 1940 Auto-Lite model IGT 4201 distributor. For some reason, someone previously installed a 5402E distributor in my 1940 356 engine! Any suggestions where I might look to find these specs if they are not in the 1954 manual?

Packard had many different distributor model numbers, are they really all different and exclusive to their particular model year and engine? The reason I ask is, my 1940 356 engine has a Auto-Lite IPG 4502E 12H distributor which is for small 8 1954 engines! The correct distributor for my 356 is IGT 4102, is there a functional difference between the two? Just rebuilt this 356 and I had to set the advance to about 15degrees to get any power and smoothness under load. Is this out of spec advance going to cause any harm over the long run?

The tester is a Fluke Networks pro 3000. Got it a Home Depot for $69.00. As far as the wire loom, it is looks and is positioned just like the one in the picture that Joe Santana posted. I would think, if there was failure due to vibration it would be where the two relay wires are bent and go into the main loom. You can see this in Joe's picture.

Want to let everyone know what a great tool the Tone tester is. Was able to pin point the wire break which was about 3"from the ground terminal on the horn relay. This was the part of the loom that curved up into the main loom. The principle of how the tester works is simple, it generates an electrical field between two unconnected parallel wires. As you follow the two wires with the "wand", when you come to the area of the wire break the "tone" volume falls off. The only down side is the Tone tester cost- $70.00! Thanks again for all the support.

Good idea. Will check around to find a piece of matching color wire loom (any recommendations?). Picked up a tone tester today at Home Depot as I an determined to find where the break actually is. Thanks for the pictures,I did a continuity test on the wire in question as my final test after chasing this problem down. I can mix up wires as well as anybody but in this case it's hard to do as there are just 2 wires to the horn relay one hot, one ground and the other end of the ground was connected to the steering box wire from the horn ring. The wire ends at the bullet connector between the relay ground wire and steering box wire are in bad shape, wonder if the bullets can be heated and the solder melted to remove and install new wire ends. If not does anyone know of a source for these original type connectors?
In the mean time, have installed a jumper from the steering box wire and the relay ground terminal and the horn works fine.

Yes, I first cleaned the relay ground terminal and wire lug. Even removed the electrical tape from around the lug to be sure the ground wire was properly soldered, it was. As you say, the ground wire in the harness is only about 2 feet long. Both the ground and hot wires for the horns come out of the main harness at a right angle, my guess would be the break is there? Would like to identify the exact location of the break but would have to cut open the harness. Even thought of pulling a new wire attached to the bad wire through the harness, but with the sharp exit angle and the fact the wire maybe completely separated I don't think that would work?

Yes, I understand and agree with every point you made. This Packard has a relatively new wiring harness so there is a splice between the steering box ground wire from the horn ring and the new harness wire going to the horn relay ground terminal. The wire opening is in the harness part, because when I undid the splice and jumpered from the old ground wire from the steering box to the relay ground terminal the horns work great. Still can't imagine how the ground wire in the harness separated?

Thanks, cleaned up ground surfaces as well as contact points inside each horn. What the problem tuns out to be is the ground wire from the bottom of the steering column to the horn ground is open somewhere. How that happened is beyond me. Gus the best option is to install a jumper wire, this wont look correct but opening up the wire harness would look worse. Any other options?

Finally got my 1940 356 engine running. New ss exhaust valves and guides, as well as, new wrist pins, bushings, new rod bearings and rings, what a job!. Thanks for the help from everyone as this was my first engine repair. The last issue now is the horn which worked before the rebuild, now it doesn't. Relay clicks, can get one horn to work sort of if hooked directly to 6volt and ground. The other horn just sort of "buzzes". Any thoughts would be appreciated.

Thanks,found a replacement that floats! Trying to repair flooded pick up and keep it as a backup. Removed solder from top to open small drain hole and removed shield from bottom. The 4 tabs holding the shield on were soldered on as well as being crimped. Maybe soldering the tabs broke the solder between what appears to be the two halves of the pick up? Is there a way to remove the screen so I can check and re-solder the edge joint around the edge of the pick up?