Another challenge with vintage patterns is sizing. You may see a pattern that states that the instructions are for a size 12 but the chest measurement appears to only be 30 inches!
Well, 50 years ago, that was correct!
PurpleKitty.com has a helpful size chart that shows measurements from approximately 50 years ago and one with currently used standards. You will have a good laugh when you see how small the sizes were then.
Using gauge information, you can size your work up (or down!) according to the desired finished size.