My 85 Caprice classic has starting problems sometimes. i already know the timings off, but sometimes when its cold, or the battery is low, it makes a sort of grinding sound. Its not the starter, but could it be the starter shims? the only other thing i can think of is maybe a bent flywheel? But then why only when its cold or the battery issue? maybe the starter isnt getting wnough power from the battery?

If it's making a consistent grinding sound, I'd look into starter shims. While you have it apart (to put shims in), take a look at the pinion for damage. If you see any, replace the starter. Also, look at the flex plate ring gear for damage.

Flex plate = flywheel on automatic transmission.