Those 2 bottom wheels look just like Rupp turbine rims to me. Take one half of the rim and put it on a sprocket to use as a template and drill holes where the mounting holes are in the rim. Put the rim halves back together using longer bolts (probably around 4.5 inch long 1/4 inch round bolts) Buy or make a spacer for each bolt (probably 1.5 - 2 inch long with 1/4 hole). Put spacers between rim and sprocket and tighten it all down. There is your drive wheel. Good luck!
