Hello, I found this thread while hunting for availability info for vacuum advance #2875096. I have answers I believe to be correct to two important things, if anyone is still interested: the vacuum advance confusion and the angled/straight slots in the top part of the shaft assembly.

I have studied these things extensively over the last 35 years of hundreds of thousands of miles of everyday use (year-round daily reliability, towing, snow, cross country, etc.), following as-built specs as closely as possible, of '67 and'68 C-bodies, mostly '68 Furys with 318 autos but a few others too, and have found some info after many years of field experience and experimentation.

First, the slots are straight for NON-CAP distributors and angled for CAP distributors (later to be CAS when it became standard in 1968) due to the nature of Chrysler's emissions controls: they only used super-lean carbs (air fuel ratios of 14.0:1 or higher, with 14.4 being a perfect combustion, btw) and heavy advances, no air pumps or other nonsense like GM and Ford, to get clean engines (and in '68 the bigger valved heads and such things) and so used these heavier-advancing angled slot shaft assemblies, in part to facilitate more retarded idle timings to reduce emissions (book spec back as far as 2-1/2 after on the 1968 318, and I have had most engines run at a setting of around 7 after and one engine ran at 10 or 12 after; this was found out by road setting the timings back a little at a time to eliminate knocks, and the engines had no loss of power due to the radical advances; this was first done by my Dad when the original car of the family was brand new, as the Chrysler and private mechanics could not get them to run right by book setting it- it would knock. Incidentally, I got my Fury wagon to blow 40, yes 40, PPM HC at idle in 1988 while set at 7 after and it had plenty of power). If you got a straight slot shaft in a box for a CAP distributor or vice versa, the part is wrong for some reason.

Secondly, the vacuum advances in my experience are as follows: on Chrysler distributors, all of the distributors I have verified as assembly line parts have used the sealed pod type advances, without exception, on all part numbers I have ever observed. The replacement parts, however, are *either* the pod type or the long-snout-with-nut Prestolite type. For a long time I only got Snout advances, until the last many years when perhaps more early production NOS has been emerging. I know this because I have ordered many 2875108 advances for my 318s over the last 35 years and have had both styles come packaged as 2875108. If you look at pictures of parts for sale you will see both styles with the same part number yourself too, if you look long enough. Keep this in mind as I continue: the 1968 318 was the most radical CAS of all, in my experience, so much so that the original aftermarket replacements for its advance were not combined with any other part number (VC-32 in Borg Warner, for example, long discontinued due to its one-and-done nature, only fits 2875108). To back this up: the NAPA Echlin parts have often been the most technically correct of any aftermarket, and they skipped over 1968. Some other suppliers combine them with 1969 parts, as they were similar. I have noted that the Snout type advances *never gave the same performance as the pod type 2875108s did* and always seemed to me to be a running replacement for the pod types because they were probably easier to adapt to different part numbers and save money (my speculation). I was never able to get the correct power curve with the Snouts as I could with an original pod type, but I think they were changed because many mechanics could not set up the original '68 318 packages by the book; they were soo radically curved that they were changed in production because they were very temperamental, even for Chryslers, though they could be set up smoothly if someone had the Magic Chrysler Touch.

Also, I have myself noticed the stacked weights vs. the solid ones, also used somewhat interchangeably but seeming to be the solid ones from the factory. (Please note that I am less sure of myself here.) Seems to me to be another example of original part vs. replacement part, though in this case no apparent difference.

Incidentally, for anyone who may drive their cars every day, even in this bitter cold, please know that it is possible to almost entirely eliminate deadspots, poor starting, and other driveability issues and have a nice smooth running, points-powered, carbureted power plant, but please note that setting up the engine properly took me many weeks of everyday studying and tweaking stone cold choke assemblies, pull-offs, carb linkages, and, once in a while, advance springs (specifically the low end). It can be done, but such a finicky system as the CAP and CAS needs a lot of initial attention to get there. I haven't had as much experience with 383s, but I'm close to getting some back on the road (I hope) and will find out soon enough.

Hopefully this long winded mess helped somebody :-) Thank you for reading.

Nice job drilling that shaft, btw.