Blacksmithdon,
My two cents. I think the best bet would be on the 261. BUT, this would be dependent on the cylinders cleaning up. I don't think they usually sleeve one of these engines, so if the bad cylinders wouldn't clean up without a life threatening overbore, you might have a boat anchor and the decision would be moot.
Would a donor 261 block be a reality? The condition of the existing scored block would make the decision for you. Good luck
Stuart
