You can usually find 'em cheap at the swaps. Just check that they are not ba$tard child abortions after being misused and abused with the over tightening.
I've seen 'em in very good condition for as little as $25 Dollars.

Good luck. It's an artform and a sense of achievement to start and make a full B-body light on the scales.

I have a few other cool ideas. I will post when they are finished and or realized in theory.
Just as a foot note, I browse an awful lot of magazines on Formula 1 racing and dirt track racing where some parts can find their way into the violent world of Drag racing. I've also discovered ideas by simply visually studying parts and how and why they function. Some parts I can make with my eyes closed, but would probably put them in jeopardy of failing if not left alone as they are.
As I say, choose your Collateral's wisely.