Chip, you mentioned crumbling insulation. Check your engine wiring harness for more crumbling insulation. You have 'the year' for this problem. Check the ground wires on the intake manifold for bad insulation and also the temp gauge wire from the harness to the clip under intake manifold runner number 1. If the insulation is off or you can see bare wire, wither get a new harness or rewire it.

I had the bad insulation problem and after I replaced mine and opened the harness up, I was amazed the car would even run.

As for the hard cranking, check the battery connection, both at the battery and at the chassis points. Also check the starter connections. Use a voltmeter to check for voltage drops. You could have oxidation, esp. at the battery chassis ground point.

Don't be apologetic for a long and informative post. It's better than 'My car doesn't start, what do I look for?'.

Please report back.
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Warren Bain .... Mainframes, Were Back And Were're Pissed.