Oil read with high idle on a '74
 

My '74 has started to idle very high, around 1,500 RPMs, sometimes more. Not sure if it's a vacuum leak or something else, I'll have a shop look into it at some point in the next few weeks.

In the meantime, is the high idle going to mess up/understate my oil read? Or can I be confident that if it reads low I can top up a quart without worrying about overfilling?