My nephew has a small engine repair shop so I asked him some questions about the 810cc. His answer follows just for general info.
Sorry have been super swamped with work but at any rate I will let you know what i can off the top of my head Yes crank shafts are forged steel very nice temper to them and if you get the tapered shaft no there Is no key way of any kind which in my opinion for a plane type installation that's gonna be a much safer route because there is no key to fail on you the center section of crank is threaded for a bolt which of course forces it onto crank shaft as you tighten it down then to pull whatever it may be off the said crank you just use all thread and couple nuts and washers to make a spanner to force it off of the shaft the newer model briggs your talking about is a great engine as far as dependability goes its very well made but there big flaw is that it has a 2 piece block to it because of it bieng made of aluminum I imagine but at any rate the thing bolts top to bottom or side to side depending on your application but they are notorious for getting themselves loosened up and well end result.as you can imagine it has an internal detination and usually leaves 4-6 small holes in the block before its done lol I have seen a few now and always tgmhe same size holes in about the same locations the solution to there design flaw is just some good ol fashioned lock tight then everything remains virtually as designed and stays together
Hi how are you doing
Hope that helps to answer some of your questions i do have a grenades block from 1 of those motors in my scrap pile from a generator if you would like some pictures of anything