Search louvering service here on the HAMB to find the closest service to you. Maybe someone will post a link to it.
There is a thread on Who does louvers here that i started a couple of years ago. If it's a smaller hood such as an "A" or '32-'35, I do mail order every day, and will guarantee the best best pattern, quality and service available in this country. My contact info is at the bottom of my post.
I had a vintage minibike chain cover punched with several rows of louvers and was very pleased with the result and price. I delivered the part to the shop while I was in Charlotte for Autofair and got it back in a week or so. Great guys to deal with! Here is the contact info: McNeill's Body Shop Jeff & Don McNeill 1909 W. Roosevelt Blvd. Monroe, NC 28110 704-238-9920
You can send a PM to Henry (DANA RED) he is in Mooreville and might be able to point you in the right direction. HRP