Big block advice

[58Yellow]

Hey guys I'm new to the forum and I have been enjoying scrolling through talks project threads. Now I'm sure my question has been beat to death but I'm not finding the answers Im looking for. I have a 58 Apache step side and I picked up a big block for it. I was wanting to use the original style engine mounts for it ( is this possible? Or do I need to get a crossmember?) I have heard that the original steering box might have some interference with the block is this true? And last question is will some block hugger headers fit the original frame?