Here are some useful links i have come across
All-data DIY Super helpful website that I use all the time for information on newer cars.
The Old Car Manual Project Original owners and service manuals for my ’39 and tons more.
Engine Compression Ratio Calculator Handy for planning a motor build.
Goodguys Rod and custom association
RacingJunk.com Online marketplace for performance and custom parts.
Summit Racing and Hot Rod parts
I’ll add more as I go...