My best tip is to contact EARLY CHEVROLET PARTS, Gary Wallace: http://www.earlychevyparts.com/ , email chev4cyl@charter.net.

Ten-eleven years ago I bought from him a good used propeller shaft which I installed in my 1922 490, together with a NOS ring gear 34 teeth and a good used pinion 9 teeth, both with spiral cut teeth. I bought the R&P-gears from a friend in Sweden who worked on a 1920 Four-Ninety restoration project, (straight cut R&P-gears, like the ones for Ford T, so he didn´t need  the spiral cut gears). He also restored a Ford T, and he found these two parts in his Ford T used and NOS parts box!

I think they are very rare, also in the US, so I wish you good luck!

Good to hear that spider gears and bearings looks OK.

@per-ake-larsson   I am working with Gary now. Thanks for you quick reply  and wealth of knowledge on the 490. Mike