The 848 is used in most of the how-to's on this subject because they are the most prevalent. Out of 6 random 235's I have in stock, 4 of them have the 848. Not that they are the best, they are just more available.
Since this is a very necessary procedure (proper steam hole placement), its just prudent unless you own a machine shop to just take it to the engine shop and have them do it. If your engine shop has no idea what you are talking about, you have your first clue as to the need to change engine shops. If you all lived in Central Kansas, no problem. Jims
http://www.jimsmotormachine.net/ in Galva, KS knows exactly what to do.
