the small main journal blocks witch where 327 where from 62 to 67 i believe.the only problem with them is that the mains wont take alot of hp ...so if your going to go over 500 i would put some billet caps on it and maybe fill it to the freeze plugs...the mains are a 2.30 not a 2.45 like a 350 or 327 block witch where made from 68-74.u can pick up some used nascar parts with the 2.30 main and they will be light weight so u have a stroked 327 .that would rev crazy fast because the crank would be only around 38# vs stock one witch are around 60#