I didn't know that.
1977 chrysler cordoba here.
over the 3 years I've owned it, I've given it tune ups, done the timing a few times, adjusted the carb, even replaced the timing chain and no matter what, I get black blobs from the muffler. it practially disappeared until recently, but it has been very cold (like 45 degrees) when starting. so I guess we both learned something new!