I had one like that from CarQuest. When I compared the gears face to face, the new one was smaller in diameter than the old one with the milled slots. This would make the pitch slightly different and I am guessing it would fit the teeth on a 12 volt starter flywheel. I sent mine back and got an original type from Ebay.

1951 GMC 1 Ton Flatbed -- It is finally on the road and what a great time I have driving it!
1951 1 Ton Completed

My Chevy Master 4 Door is on the Road!