just changing the timming set is easy. use the keys that are on the old one. line it up dot to dot like the FSM says and you will be fine. Advance roller will be just fine. the biggie is to make sure the marks are correct when you do the dot to dot. look at your old one as to how far from the keyway the real dot is. some are not marked correctly so u have to check them with a known good one. i recently had a mis marked one on a motor and it dropped a vavle and ruined about 2k in parts. see att. and u can always ask on here for more help.