See my quite recent post on this one John...'Engine shaft riveting'...Scroll down the forum page, Feb.22nd was the last post on the subject by Nathan...There is an alternative and easier method for changing shafts..Ian
As I noted, I haven't looked into this mod. in detail...I only know that some racers do it to avoid loose rivets/shafts which can happen under racing conditions...
Once you have determined the thread size, length and head type required any industrial fastener company will be able to supply what is needed...Ian