I'm helping a friend get his 383 started in a '67 Polara. It measures 8V at the coil when cranking. Is that too low to fire the plugs?

That sounds about right to me.

I think it really depends on what your ignition system consists of.

Stock, probably about right for an older unmaintained setup.

Thanks. It is a stock single point ignition system. The engine hasn't run in a few years.

The number I remember from the 60's which'd be points like yours is 9.6V min cranking. Not sure if 8V is the issue. More info on what is going on with the rest of the system. What is makin you think ign issue right now? Cranks good? blue or yellow spark? carb/fuel up to snuff? EDIT With more thought that 9.6V would have been at the batt tho with adequate voltage drops it would not be in the eights at the coil

When cranking, the ballast resistor should be bypassed with the ignition switch on "start". The coil gets full battery voltage which is pulled down by the load of the starter. 8 volts sounds about right or maybe a touch low. Still should be plenty to make a decent spark.

You could check voltage at the battery while cranking... if its 8 volts or a bit more, all is well with the wiring. If you get much difference (more than .75 volts or so) there may be some dirty connections (bulkhead or ignition switch or other).

Thanks for the info. We'll check battery voltage when it's cranking. It's getting fuel. He installed new plugs, cap, rotor, points, condenser, and coil. Timing is set. He pulled a plug and had spark, but not sure what color.
One time it sputtered for a second before shutting off. He's been using a remote starter so the key has only been in the run position when testing.

With the key in the run position he is getting power through the ballast resistor to the coil which is what you are measuring. The voltage is correct for run. The start position of the ignition bypasses the resistor an give full battery voltage to the coil.

Check the BATT voltage when cranking. If it is also 8V then you don't have an ignition problem but you might have a BATT problem or a wiring problem.