383 Distributor Confusion

Sometimes I feel like I am going 1 step forward and 2 steps back.

Tried to put in what I thought was the correct distributor for my 383, that I bought a long time (15 years) ago, based on the number on the housing. Should be 2875358. But when I put in the motor it wont go in all the way. Oil pump shaft is seated down, btw.

Searched and found this previous link: https://board.moparts.org/ubbthreads/ubbthreads.php/topics/1904196/re-distributor-shaft-lengths.html
When they say "Measured from mounting surface to end of distributor shaft." this means the flange/base that seats in the block top surface? Thats what I thought.

I dug out an old 440 RB distributor I had laying around and sure looks the same to me. So I guess I have a rebuilt that someone put a 440 shaft in? Well that sucks. Guess I got to find a 383 donor and swap.

And to add to my confusion.
For the 1968 parts book, the distributor should be 2875358, which I believe is a single point Chrysler unit (not Prestolite).
For 2875358, the correct vacuum control should be 2875096.
Attached is a FSM photo of Chrysler and Presolite parts breakout. My 2875358 looks like the one on the left (Chrysler) but 2875096 vacuum control looks like the one on the right (Prestolite).

So is the FSM wrong or parts book wrong?

I'm no part number guru, but I've been down the same road as you and you've almost for sure got a 413/426 wedge/440 distributor. Those are about 1" longer than the 361/383/400 distributors and look otherwise identical.

You have another option though. Years ago I switched to electronic ignition and I had a 383 in the car at the time. I knew I was going to drop a 440 in it (motor 1/2 built). I found a Direct Connection adapter to make the 440 distributor work in my 383. It was an aluminum spacer about 1" thick that fit directly under the distributor and above the block. It also came with a longer distributor hold-down. It fit/worked like a charm. I probably still have it somewhere.

I'm no part number guru, but I've been down the same road as you and you've almost for sure got a 413/426 wedge/440 distributor. Those are about 1" longer than the 361/383/400 distributors and look otherwise identical.

You have another option though. Years ago I switched to electronic ignition and I had a 383 in the car at the time. I knew I was going to drop a 440 in it (motor 1/2 built). I found a Direct Connection adapter to make the 440 distributor work in my 383. It was an aluminum spacer about 1" thick that fit directly under the distributor and above the block. It also came with a longer distributor hold-down. It fit/worked like a charm. I probably still have it somewhere.

Hey, I found it at Mancini for $65
http://www.manciniracing.com/rbtobbldiad.html

The Chrysler vacuum advance is as shown with the tang to fit the slot on the cap and a pressed pin on the arm for the breaker plate,the Prestolite has no tang for the cap and a hole in the end of arm for the pin located on the breaker plate.The design of the advance changed in 1970 but the configuration is the same.

Ah ha, so now it makes sense, thanks! At least one thing went right.

I thought I found the correct shaft NOS from Brad's but his site was wrong. Knew that sounded too easy to be true.

I guess I will go with some other 383 shaft and wing it on the springs. Unless I can find a kit to match the correct springs. Anyone know of a source for finding sprjnfs by application?

This annoyance doesnt stop. So I was able to find an NOS shaft about as close as possible to mine. This is for the 383 manual trans A-body distributor versus my auto. Short of an exact match, probably as good as it gets. I am smiling.
I get the box today and open it up, NOS box, sealed tight with original staples, never opened, wrapped in wax paper, feeling good. Size up the shaft and it is perfect length. Then I look and dont see the hole for the roll pin. NOS shafts dont come with this hole??
Yes, I can drill it, but man, this is not getting any easier. Drilling on a round hardened shaft is gonna be tough. I have a drill press, but need to come up with a way to ensure this thing does not move. I guess clamping it on some wood could work.

Interesting note. The 383 shaft has a different arrangement of the advance weight holes then I recall seeing. They are on an angle, unlike the 440 shaft I have and other distributors have. Weights also dont throw out as much before the springs kick in.

Good luck with that , 69 383 manual trans A body used a PRESTOLITE distributor, that is why you see a difference. Also note the numbers on the points caam, the one on the left has 24 degrees mechanical advance, the right has 31 ... multiply the stamped number by 2.

I have a bunch distrbutor parts, I might have that shaft NOS ???

That really big angle causes the advance to be more for a given increase in rpm. The '68 Auto and Manual have very similar advance rates, so that something else that doesn't seem right (edit: or I should say different) about the NOS shaft assembly. I think its for something that needs a quick advance all the way to the top. Also taking a closer look at the primary springs in the photo the one is heavier and less coils, so the start would be at a higher rpm.

Graphed the two advance curves. The primary springs were probably the same, the automatic had a secondary spring with a little shorter loop and/or the adjustment tab was a little further out compared to the manual.

Installed on their respective engines at the spec base timing ( 0 for manual, 5 BTDC for auto) they provide very similar mechanical advance curve.

If you have a machinist's vise drilling that hole is not a problem. It's been a while since I did one but I can't recall having a problem drilling. The problem is putting the nylon retainer on and drilling it AND the shaft in one pass so the holes all line up. As I recall the procedure is in the FSM.

If you can find a NOS shaft 2875 175 in your stash, this may help me understand what is going on and keep my mental state solid.

The 68 FSM (attached) says both the manual and auto are Chrysler built. Also, take a look at the advance spec stated for at the distributor (which would be the number on the shaft?), the 15.5 for mine would be below the upper spec for 2500 RPM.
The 68 parts book show the same part numbers for both manual and auto distributors for the cap, rotor, points. Just the shaft and weight sets are different. Prestolite would be a dual point and different internals, I would think.
Are the FSM and Parts book wrong?

So now I'm confused. You say your correct distributor number is 2875358. You have one with that PN stamped on it. The correct vacuum advance as per the parts book is 2875096. You have one with that PN stamped on it but it doesn't look like the illustration in the parts book. Does that about sum it up?

If so, I would assemble the distributor and use it. The stamped part numbers all agree with the parts book numerical listing and there is no reason I can see not to believe them. The illustrations in the parts books in the past with other components have been inaccurate, this may just be another case of that.

6PakBee- The problem is that the shaft in the one he has is too long. So he's trying to find the correct shaft or a correct example to compare with.

NJmopar - Did you notice the FSM part number and the Parts Book stamped numbers don't match?
2875xxx vs.
2857xxx
Since all the part book numbers indicated distributors are stamped 2875 xxx, I would guess that is correct. Yes - I checked '69 Dodge FSM and its 2875. I'm going to guess the vac advance you have is correct if it fits even though it is the design shown with the prestolite.

The weights are the same, p/n 1881 955
I think the only difference between auto and manual versions will be the governers (cam & stop plate in parts diagram) in the package with the shaft assy.
Cam and stop plate: auto 2642 848, manual 2875 380.
the springs package: auto gets 3004 169, manual 2932 707.

Funny, in all the times I looked at the pages never noticed the transposed numbers. I guess the FSM editor didn't either.

I will be away for a little while so if anyone has a NOS dist or shaft please take a look at the weight slots, as I am really curious on why these are slanted. Like to know before I pin the NOS one and find out I am wrong.

And I found more proof the dist I thought was NOS was rebuilt with the wrong shaft. I just noticed the oil hole for the top bushing oiler isn't there. I guess they used newer bushings with no holes.

I made a mistake, the picture you put up made the 383 one you have look like a Prestolite and for some reason I thought you were talking about a 69 A body 383 which has a Presolite , the 68 does not.

One thing you are fixated on here, and causing you some anxiety, is the ILLUSTRATION in the parts MANUAL, it's an ILLUSTRATION, not an actual representation of the production line parts for all models. The vac can you have has the correct part number and it is for the Chrysler distributor. The vac can in the ILLUSTRATION is more prevalent in 69 and later.

Are you building this car to 1000000% factory stock and what are you actually working on, I missed that part ?

I realized that. What I don't understand is all the angst about a gazillion component PN's. Get a shaft out of a B series Chrysler distributor, see what the appropriate weights and springs are and be done with it.

I am working on 68 383 GTS convertible. Trying to get as close to original as possible, within reason. For example the dist I have is correct part number on housing but dated 69. I can live with that.
My main concern was the shaft length which has morphed into other points. The vac advance style I only saw on prestolite dist and the FSM had me concerned.
The obsession on the correct shaft with springs was just me trying to match close to stock as possible. Which then peaked my curiosity on the different looking weight slots.

Looks like I have all the pieces, just need to carefully drill the pin hole next.

Well it certainly appears that the one you bought has the correct length but the cam plate and weights are special.

IMO it's definately worth asking for pictures of known correct parts. What seems most odd is the weights made of built up steel plates - the part book indicates it should have the same weights as most other distributors. That's what makes it appear to be a special, low production item. And if it is special but for some other application it would suck to go through all the trouble of drilling and installing it when a) it may be valuable to someone else b) you could get a fairly correct advance curve using a shaft from a good used 383 distributor. Since you have a little time, why not see what knowledge and pictures are out there.

Here's one for sale that has the same p/n as yours. Whether its worth asking them for info/pics or even buying comes down to one of those time/money/risk decisions, everyone is different.
http://bluestarperformance.com/parts/ele...-1968-used.html
They claim the build date code is '67.

Some pictures of built up steel weights apparently from an earlier cast iron distributor for a /6. So I'm probably wrong about it being a special low production number part.
http://www.allpar.com/fix/electrical/distributors.html

I don't know what the '69' signifies but the "2 8" following the part number is the date code. This would be the second week of 1968 which would be correct for a '68 application.

Nice find thanks. I sent them a mail to see if they can look inside. Also asked what part number is on their vacuum advance as it appears to be the other style.

Beat me to it ... the 69 MAY be the number that is on the Broadcast sheet showing the number of the Distributor that was used for the engine build, the distributor isn't installed until after the engine is painted I believe.

NJ, what is the scheduled build date of your car?

Actually it is backwards,the early weights were cast one piece,later were laminated.

My build is Oct 4 67 I think. Traveling so can't see my notes. I misread that 69 for sure.
So I contacted bluestar and they were very helpful. I sent them the pic above showing the weight slots and asked if he could check that dist. Here is the comment.
"checked it out,and the advance weights are the same as the image on the right.They have the slanted angle.Maybe slightly more rounded at the far end.They have the L15.5 stamped on them as well. The advance unit does not have a number,as far as i can tell,some did not. "
So my mystery NOS shaft looks correct.

Awsome. Jig it in a machinist vise and drill away!

Except for the weights , what is the date on the box it came from ?

Here is the box it came from. Staples and tape were opened what seemed like the first time.

In conclusion: Set the shaft end play, marked the spot, then drilled in the drill press after carefully checking for squareness. Went pretty smoothly. Shaft is in, points on and set.
Thanks for all the input.

572 , May 1972

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.

From my study, the cast weights are Chrysler(part number is on it). The stacked are prestolite. Prestolite also made single point distributors with Prestolite type caps, and Chrysler caps; so there can be subtle differences in those shafts too. The shaft should have part number on it for prestolite.

Weights are interchangeable.