I have several old vintage Briggs engines with kick starts, and lever starts. Some are on the pto side, and some are on the shroud side. I think it would be great if you could make one for the more modern Briggs flat heads, but I think it might be difficult to make one that works well, and is reliable, but what do I know. Go for it, and good luck!:thumbsup: Here are a few of my oldies.
Matt