I know that magazines like “Motor Trend” and “Car & Driver” have reviews and road tests of cars but which magazine or website have specs for cars with torque curves? I tried to search the Internet for specs for cars with torque curves but I can’t find what I need. I need specs and torque curves for vehicles that I’m using in my games.
is the one I use for all the different specs, width, height, top speed, and many others. does not have the torque curve (see below) but almost everything else. Click the car brand, then the model, and it is all there 
For torque curves you want to find a “dyno graph” of the car. For example, is one for a Ferrari F430 (the second post) *EDIT - Sorry it wont show it without registering… just skip link, and search as detailed below.
http://ferrarichat.com/forum/360-430/337117-f430-hp-torque-curve.html
So try searching for “dyno graph …” where “…” is the name and model of your car. Make sure you convert the values to metric (if you get one in foot pounds (ft lbs), make sure to convert into NM, which is used by UE4)
Hope that helps!