I put a starter on a 38 RC that didn't have one originally. I took a SC starter and had to re drill the set screw hole to line it up right. Then I cut some .010" or so ( don't remember the exact thickness) sheet metal in a 1/2" x about a 30" strip and rolled it under a AC WC ring gear on the case RC flywheel. The AC ring gear is a sloppy fit on the flywheel with no modifications. I heated the ring gear and shrunk it on top of the flywheel and shim. The starter drive seems to be a rough mesh, a little noisy, but it works. The gear teeth may be slightly mis matched. I have a RI here with original starter that we used to line things up for the hand crank RC conversion. Makes a good conversion at a Case collectors price range.