The change to the main bearing flange was also cut in the blocks before the 'official' change... I have seen a few blocks earlier than 74 with the wider thrust flange machining...
Check your block before ordering...
However, the early style bearings will still work with the wider cut flange...
I have run into that same thing. Since blocks were only cast at certain times of the year, when your dealing with a 73-75 block, you really need to see which block you have.
