I replaced the main sheet blocks (fiddle and single with becket) this summer. The first difficulty was removing the merriman blocks -- I couldn't find a way to unclip them so I sawed them off. Then, I discovered that the lip on the block stand prevents the attachment of a standard shackle. I ended up lashing the new blocks to the stands just to get me through the summer, but I have yet to find another type of shackle that will fit the stand -- I will probably need to grind down the collar on the stand a bit to allow the standard shackle to fit. What a pain, but the old blocks were shot, so there you go. If I could have figured out a way to disassemble the Merriman's and replace the sheaves, I would have, but they seemed permanently sealed.
