Bob,
Check out the Independent Scratchbuilder Forum here on SlotBlog and put your prodigious Retro building skills to work. As far as weights, I can give you a couple. "scratchbuilt.com" is also another useful sight. If you're looking to build replicas then you'll need to look on E-Bay for wheels, tires, guides, etc. If just for racing jaildoors then you can use modern components. Alpha has a number of colors in 7/8" dia., you'll just have to cut down the width (from the outside) for clearance. TrueScale offers some nice 3" wide bodies to fit the general width rules.
In the Retro Forum here on SlotBlog there is a sub-forum on scratch-built jaildoors using the 1966 R&C rule set. Personally, I prefer the 1967 Car Model rules you were sent last week.
Don Weaver
Don Weaver
A slot car racer who never grew up!
The supply of government exceeds demand.
L.H. Lapham
If the brain-eating amoeba invades Washington
it will starve to death...