Reddit mentions of Competition Car Aerodynamics, 3rd Edition

For aerodynamics competition car aerodynamics by Simon McBeath is good starting point for aero.
Amazon link
Competition Car Aerodynamics 3rd Edition https://www.amazon.co.uk/dp/1787111024/ref=cm_sw_r_cp_api_LyUezbWXPXNS1

For engine design, I've found the tuning books to be good for a base point. The Books by A Graham Bell are good starting points
Amazon link.
Four-stroke Performance Tuning (4th edition) https://www.amazon.co.uk/dp/0857331256/ref=cm_sw_r_cp_api_1BUezb9J526WQ

I'd also recommend some of the books from the speed pro series. Should be noted there are books by bell for 2 stroke engines should that take your fancy

Transmission wise I'm not to sure. I got all my knowledge of those through practical experience and engineering maths.

Hope this helps

Aerodynamics, especially automotive aerodynamics, is a very complex subject. If you pursue this path in undergrad you'll need to get comfortable with advanced calculus and physics, as well as fluid mechanics. From experience, I would highly recommend getting involved with the car project teams at whatever university you decide to go to if you want to pursue a career in motorsport. Motorsport teams are looking for people that are not only exceptionally knowledgeable in their field but also passionate about racing.

As for things to read, there are loads of books on the subject. Understanding Aerodynamics by Doug McLean and Fundamentals of Aerodynamics by Anderson are two aerodynamics books sitting on my bookshelf.

For automotive/motorsport aerodynamics, the following are good books from my bookshelf:

Competition Car Aerodynamics by McBeath

Race Car Aerodynamics: Designing for Speed by Katz

Aerodynamics of Road Vehicles by Schuetz

Note, Aerodynamics of Road Vehicles is a full-on textbook and may be beyond what you're looking for, but it goes into great depth on a number of road vehicle aerodynamic topics.

One last book I came across on Amazon is Amateur Car Aerodynamics by Edgar. I haven't read this book, but the title sounds like the language may be more suited for people who don't have a background in fluid mechanics.

If there are any specific topics in fluid mechanics/aerodynamics that you are looking for I may be able to help find some.