Mild 318 misses at 3000rpm

It would be interesting to find out the polarity.... if it is OK, then is says that the long lengths really messed up the reluctor pulses .... maybe induced from the spark plug wires.... those particular spark plug wires are not standard resistance wires and so may produce a higher EM field around them. Or running too far in a harness somehow got noise pulses into it. But that would seem to cause random a lot of the time..... and not a steady retarded by 32 degrees like you found.