In general, garden variety FE blocks are similar throughout production ( there are no "bad" blocks to avoid ), but with different characteristics to watch for. You already mentioned the 2 and 4 bolt motor mount bolt hole. Early blocks like you have often don't have the bolt hole at the front passenger side for the later alternator mount, something to think about. The early blocks also take a different thrust bearing, so a different bearing set. There is a work around for that. As far as the crossbolting, by your picture your block doesn't have what have been dubbed "knorbs", the extra bit of casting from the block skirt toward the main caps that 427 blocks have. That is the feature people have mentioned they have found on non 427 blocks in the 1964 to early 1965 era. The "knorbs" make it relatively easy to add the 427 cross bolts, I don't know exactly what is involved in trying to do it with a regular block, but I believe it can be done. By the way your date code of 1H22 is August 22 1961, so it would probably be for a 1962 model year vehicle, since most would have been introduced in September. All FE blocks should be sonic checked, especially in a performance application, don't believe anyone that tells you a particular year or casting number has extra thick cylinders. I'm sure people will add some other thoughts here.