>I had a '91 Grand Prix with EFI and it ran for about 30 minutes, after the
>alternator went, before the voltage got to low (I believe 10 volts) to keep
>the engine running. I didn't need my headlights or use turn signals, radio,
>or fan. The Grand Prix had a much smaller battery than my '84 Westy has so I
>assume my Westy could go much further.

You didn't look in the Pontiac owner's handbook, under the brick in
the trunk toolkit.

There's a panel on the bottom of the passenger-side dash. Open this,
pull out handle and turn to hand-crank magneto to keep engine going...