Ignition/start & other questions-440HP 1970 Chrysler 300

ppsi said
checked for voltage and had it although only about 10.75 during cranking?

Yup. That's normal.

I've seen other posts talk about the voltage at the coil being low during cranking due to battery load while cranking.

Exactly. Line voltage drops when load is applied; cranking is a heavy load. You'd see the same ~10.75v across the battery itself during cranking.