Just got to thinking about it alittle bit. I'm sorry you are tired of looking for a decent 340 block for $500 or less, and you don't want to spend the money to bush the block you already have. BUT, both of these option are a hell of alot cheaper than buying a brand new block.
So I guess my...
You can use a 48 degree head on 59 degree block, but not a 59 deree head on a 48 degree block. All R3 blocks are not siamese bore. You can get an R3 block 48 0r 59 degree with or without siamese bore.
My 340 resto block is is a 59 degree non siamese R3 block with the extra head bolts milled...
Hey, sorry about the first post being about selling parts. I just thought i might offer them to aguy that dosen't live to far away. I really don't care if i sell them at all.:oops: