When you have the block casting number you need to check these web sites. Final determination may require dropping the
oil pan to see what type of block it is.
The 385 Forum where the racing BB 460 Ford guys hang out.
http://www.network54.com/Hide/Forum/85220
Great site describing the early 429s.
http://fordifiedracing.homestead.com/460tech.html
The 4 bolt 429 SCJ blocks have the main caps dowelled to prevent cap walk. The extra thick 2 bolt block is not dowelled.