Heirloom recipes often call for measurements of 'coffee cup' portions. How much was in that cup? It can make a big difference to your recipe especially if you are baking a cake. I have coffee cups in my cabinet that range in size from 6 ounces to 20 ounces. I suggest checking the portions with modern recipes and making your best guess. Just be sure and make notes of what you changed in the recipe.
Other recipes are simply made by the 'bowl' or 'pan'. Mom made her Cornbread Dressing every year in my Great Grandmother's bowl. One of the few possessions that belonged to Mamie, it was treasured by all of us. The bowl is in retirement now because it developed a fine crack several years ago. That Thanksgiving, Mom and I were left wondering how to measure the cornbread for the dressing.
Having made it in the bowl all these years, she measured by eyeful in the bowl itself. Before I was old enough to help cook, I helped crumble the cornbread into that bowl. But neither of us could guess how many cups were in it and there wasn't another bowl in the cabinet close in size. It really didn't seem right not to use the bowl at all. We finally decided to use it for measuring the cornbread only and mixed the dressing in a large stock pot. Everything turned out fine and the treasured bowl was put back in its honored place on top of the refrigerator. Now as long as I don't misplace the special stirring spoon.....
Here's a vintage Turkey and Dressing recipe from the late 1800's.
Turkey & Dressing
A good-sized turkey should be baked two and one-half or three hours, very slowly at first. Turkey one year old is considered best. See that it is well cleaned and washed. Salt and pepper it inside. Take one and a half loaves of stale bread (bakers preferred) and crumble fine. Put in to frying pan a lump of butter the size of an egg; cut into this one white onion; cook a few moments, but do not brown. Stir into this the bread, with one teaspoon of salt and one of pepper; let it heat thoroughly; fill the turkey; put in roaster; salt and pepper the outside; dredge with flour and pour over one cup water.