I think my 727 is fried. Now I'm at a crossroads...

Pulled the plugs yesterday and they're all rich. My wires are new and I've confirmed continuity, plugs are heat range 5. I will say that I richened the idle a bit because I suspected a lean condition, so that may be the cause of the rich plugs. I'll do a compression test once the engine is back in.

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Are you sure you have the right plugs? They look like GM plugs, short threads.