[blykins]

If you're gonna swap mainshafts, you might as well freshen everything up. It's worth the time and effort to make sure everything's perfect. You'll have to change the mainshaft bearing anyway, so might as well upgrade to new parts....Also if you change the mainshaft, might as well put brand new bronze synchronizer blocking rings, needle bearings on the clustershaft, and new o-rings on the shifter cams....since all of it has to come out anyway....and you wouldn't wanna put a new mainshaft in and then have the o-rings weep tranny fluid after you install it.

All of this stuff is really cheap....really no reason not to. I bought the road race kit...comes with beefier main bearings....comes with about everything really.....assembly lube...paint....etc....