[PhilS]

The side oiler was introduced in production cars in 65. Big cars and Cobras only to my knowledge. The early FEs oiled from the center or top as some call it. With the new block came new heads. The early street cars had low riser heads and intake and the side oiler had medium riser heads. The high rise version was comp only. Some racers actually prefer the old blocks to the later version. Something about oil timing. The medium riser heads are much superior though. All of the 427s and even a few 406s were cross bolted. The late 427 used in the early GTE Cougars was different still. A step down from the last great 427 of 67. They are prone to core shift and must be sonic tested for even small overbores. Often they require sleeves. Cleveland heads are the ones used on Boss 302s and 351s as well as Panteras. Quite different than the Windsor heads. The Boss engines got 4 bolt mains too.