As to spark plugs and wires, they all got mixed up in the 60s and later, when the cars were new. Stock coils were abt 30KV, as I recall. Many ign parts vendors want you to use THEIR coils, which are generally hotter, up to 50KV, BUT also consider that the coil will not produce that amount of voltage on every spark, just when it needs it to fire the plug. As an example, one time after j-gapping the plugs on our '66 Newport 383 2bbl, they all hit 8-9KV at idle on the Sunn scope at the local Chry dealership, at idle.
When the cars were built, Champion was the "captive brand" plug that Chrysler used. That was when Champion was its own stand-alone company. Since the 1980s or so, it became a property of "hedge funds" which bought other older, stand-alone car parts brands. BTAIM
Back in the 1970s-1980s, what worked at least as good as the Champions did was the Ford Motorcraft plugs! Better durability and resistance to electrode erosion, as to "gap growth" and such. In the middle 1980s, I discovered the NGK V-Power plugs and started using them, due to their gap design being better at getting the fuel/air mixture fired-off. Later, their Iridiums, for the same reason.
Plug wires? I started using the magnetic suppression wires from Borg-Warner in the 1980s. Before that, the first Sorenson Mono-Mag wires, one of the first magnetic suppression wires of the later 1960s. The B-W wires were termed "Kool Wire" wires. At least on my '77 Camaro, they looked just like the OEM wires, but with plug boots about twice as thick. That particular set has been on the car every since, now with over 500K miles on them. I put them on everything! Now as BWD brand at O'Reillys. Great pricing, great durability, great longevity as there is no carbon conductor to degrade with time. And they fit well, being pre-terminated. Usually in black wires and boots. I consider them, like the NGK Iridium plugs, "lifetime" in more ways than not.
The ONLY plugs I used that were chunked "before their time" was a set of Bosch plugs in about 1975 (as not being a good option for the Champions) and the famous "Split-Fire" plugs (too expensive, over-promoted, no durability) in the late 1980s.
When I bought my '80 Newport used, it has a set of Autolites in it. They were working fine and burning clean. No issues, but immediately after putting in that first set of NGK V-Powers, it immediately acted more responsive and "happier", which meant it was nicer to drive, but no more mpg.
The "minefield" is not nearly as scary at it might be, to hear some tell it. More "universal" in more ways than not, from my experiences.
I'm not sure the current "Champion" is as good as the Champions which came in the cars when they were new. Main thing is to match the heat range! Go one notch colder, if necessary to get a good match. Anything in the J-12Y or J-13Y range equivalent should work fine, adding "resistor" to the mix, if desired.
In the current Champion nomenclature, "R" = resistor, "J" is the thread length, "-12" is the heat range, "Y" is "extended gap" (which is better), and "C" = copper core.
What brand of plugs are in the engine now?
Just my experiences,
CBODY67