With permission from the owner of the Spirit of Speed licence, @jjonessteele, please find you a 3GB archive from the studio Broadsword Interactive containing source codes, documents, assets (cut tracks?), dev tools etc. for SOS 1937 and 2002 (Unreleased) Dreamcast/PC.
Many thanks to John Jones-Steele for his generosity, his development studio:
https://www.west-coast.wales/Thanks also to @TheDCJunkyard for allowing me to contact him.
Thanks also to @LemonHaze420_ who took care of the Github links
Please note that the assets cannot be used in any commercial game. The cars in particular were licensed from Mercedes, Alfa Romeo, etc. They could only be used in Spirit of Speed, because they wanted to support a small independent Welsh company!
To read and download below: