I have no doubt the later Edelbrock made things work better than the OEM AFB did, just the normal progression of things mechanical. I concur that the normal tune-up parts for the points ignition will be the same as for an electronic system which might replace it. There are some good, OEM-level parts out there, but trying to exactly duplicate the orig OEM specs might be a bit of a challenge, sometimes. In many cases, some of what used to be common stuff is now at elevated price points as they have been superceded by upgrade parts. Like resistor spark plugs rather than non-resistor plugs. Plug wires certainly will be better, but getting the set with the right boot angles on which plugs to match what the car had on it from the factory might be something else which might be different.
On the issue of ignition distributors, it's the sharpness of the distributor cam lobes which is important. What the rubbing block of the contact points "rubbed" against to open and close the points. Some liked the "high spring tension" for allegedly better higher rpm performance, but that also meant more wear on the points' rubbing block and that distributor cam lobe, especially if the vial of point lube was not used. Even with normal points, the sharpness of these cam lobes will become worn and rounded-off. You can still set the points for the gap sped, but then the dwell spec will not be in range, when this happens. Plus, the height of the lobes can vary from cylinder to cylinder, which can ultimately affect the timing at each cylinder as a result. Things we didn't consider or worry about back then.
Many suppliers, including RockAuto, sell a "conversion kit" for electronic ignition. From the pictures, it might well be the same as the Pertronix unit, in a different logo wrapper, but I don't know that for sure, just going by the online pictures. I used to advocate for the old Mopar Performance/Direct Connection Chrysler electronic ignition conversion kit, which was all new OEM-spec, production based parts. In one kit at a good price. But from other poster, I not understand some of their vendor sourcing might not be what it used to be, fwiw, yet Mancini Racing has a similar kit they put together, which some have used.
Getting the combustion processes back to spec is a good idea, provided they seem to be a bit "off". As for further diagnosis, I'm going to recommend something other than "parts changing", which has happened from my own experiences with the '66-'70 383s our family has had (and still have). That would be, first, a "Cylinder Balance Test" to take one spark plug wire off at a time, or using a diagnostic machine to electronically kill one cylinder at a time. The watch for a weak cylinder that has less rpm drop when that cylinder is deactivated. Then, follow that with a compression test, using a flex-tube tester rather than one you press into the spark plug hole, to verify the weak cylinder. Additionally, if you have or have access to a Leak-Down Tester, that might further pinpoint where the compression loss might be.
From our experiences, if the car has close to 80K miles on it, then it could very possibly be a burnt valve on #7 cylinder. Which was a common issue on the '66, '67, and '70 383s we had. When the valve guide wears, the valve guide seal wollers-out and oil consumption can increase a bit, BUT it also lets the valve not seat firmly, even be a bit off-center when/as it seats, which leads to exhaust leakage on the compression stroke. Which can lead to a "hot spot" on the valve, which can then cause further erosion of one part of the valve's outer circumference.
A shade-tree check for a burnt valve is to take a red shop rag and hold it over the exhaust pipe tip as the engine is idling. With the burnt valve, in addition to it not holding compression, it can also "suck" on the non-compression times. Which will visibly pull the rag into the pipe, for the split second that the negative pressure pulse exists. It's visible as you hold the rag loosely across the pipe's end. With a dual exhaust, you might need to block the pipe on the pass side where the heat riser is?
A vacuum gauge might also be a diagnostic tool, but with varied results, at least for me.
The can will have a rough idle in gear, less so in "P" of "N". Once at cruise, it will be smooth, but when needing additional power to go up a hill, that's when you notice the power loss most, by observation.
Might not be what you're looking for, just stating my own experiences over the years, from back when those cars were "just used cars".
As for replacement parts, the orig spark plug spec was Champion J-10Y on the 4bbls and J-14Y for the 2bbls. All non-resistor plugs. No problem using something like a J-12Y. Chrysler later went to a J-13Y for the 400 2bbls in '72, They all showed the same insulator color on a stock engine, back then, from my experiences. Personally, I got great results with Motorcraft spark plugs back then. Even better durability than the Champtions, but the Champions weren't bad either, for that matter. Going to a later version with copper core is "no issue", so long as the heat range number and gap style ("Y") are the same. Gap at .035"
As I recall, the distributor end of the spark plug wires were all "straights". All of the plug ends, except for #6 and #8 (which were "straights" and "over the valve cover" routing) were right angle ends. Chrysler started using some 135 degree rear plug boots on the '72 400s. They look neat but can be broken if they aren't pulled off correctly. Check the listings at TockAuto for related images of the wire sets, for reference and pricing. Then look for local sources of the same or similar products. I used to like the old Borg-Warner Kool Wires magnetic suppression wires, but for normal use, a quality brand with the correct ends is more important for correct fit and performance.
Nothing special about the cap and rotor, as long as they come from the same brand, to me. The OEMs were the tan color. Brass contacts or otherwise, a stock motor doesn't need anything special. Same on the coil and coil wire. Pertronix might want you to buy their high-output coil, but others use a stock coil, as Chrysler did. I've tried replacement coils in the place of the OEM coils and found no difference in performance. So if the current one works, it'll probably continue working, from my experience.
Before you get any deeper, I'd suggest getting the cylinder balance test done. Might be that your scope can do that? Or perhaps after a close-tolerance spark plug gapping session, you can tell the weak cylinder by its lower ignition trace "spike", as the weaker cylinder will not have as much compression, resulting in the coil needing to build less voltage to fire that particular plug. When I would do that, then take the '66 Chrysler to the dealer to get the speed/mixture adjusted ( I had no dwell tack at that time), the plug firing traces would all be within 1KV of each other at idle. So, you might play with that and see what happens.
If you remove the rock shield from the lower steering coupling, with one Phillips head screw, it makes access to #7 plug almost good enough to not need a wobble socket on that plug. Just don't lose the screw and put the shield back on when done.
Sorry for the length and the fact that I might have mentioned some things you might not have expected, just my own experiences.
Enjoy!
CBODY67
