Max weight is the weight of a Station Wagon which is 1 pound 5 ounces. If you are on FB there is a page of Hubley Derby Racers.
https://www.facebook.com/groups/1575059066095506/
Here are some photos of the ones I have done in the past few years. We are pretty relaxed about the rules too. But we have two classes one for Seniors and to try to encourage the youngsters a class for under 18. But I think we could make that cutoff at 50 and not change much.
Some of the guys in our club use a wheel hub from Trailer Wheel and frame part
# WQUA 84545 and then anyone with a spin balancer can do it.
sorry wrong part number should be 84555
There is something that no one has touched on yet. Where I live and in most parts of the U.S. gasoline contains up to 10% ethanol. There are a few places where you can buy pure gasoline but not many. Just make sure your car can handle the alcohol gaskets, seals and float.
On the 28th you were going look "tomorrow." Today it the 30th, I am wondering did you get it? Personally I like to SW cars and if I ever had to start over that is what I'd do. I am not a purist but I'd have to do something about the color. Maybe even just paint the fenders black. I did a little...
Mine is a driver and I use the screw jack of of a F150 pickup. Haven't needed it too often but it works just fine and it is small enough to fit under the back seat of my tudor.
The axles use 4-40 fillister head screws. I have found them but it takes a good hardware store. I usually use one a little longer so it doesn't tend to back out. A SMALL amount of locktite helps too.