Some guy was using a bank of 8 automotive ignition coils (like the one on your 65 Chevy
) as an output match from a single big pentode to a speaker. Seemed to work OK as an autoformer.
They were in a parafeed with a blocking cap arrangement.
Bandwidth notwithstanding, this could be the answer to the shortage of cheap mod transformers, and would cut down on a lot of unnecessary driving in the neighborhood....