Classic/Antique Car Repair: improve gas mileage, old boats, gas mileage

Question
i have a 73 caddy sedan deville how can i improve my gas mileage and i had a recent power drain , but it happen right after my horn would not shut off

Answer
Not a lot can be done for the old 'boats' but these are the standard answers:

Put larger and dual exhaust on all the way from the engine out the tail.

After market carbs, such as Holley due amazingly better than factory.

Timing can due a little, but in my opinion does more harm than good.

Also, air pressure in the tires is as important as you hear in the commercials.

Don't forget to get all the excess weight out of your trunk