I am unsure of the 292 fit requirements but can speak to the 54' crossmember in a 47-53 truck. I put this crossmember into my 50' with a 54' 235 and it is pretty simple. You grind the rivets off the early one and the 54' version will only require a small amount of hole reaming to fit. The holes are only about an 1/8-1/4 inch off in total and the 235/SM420 bolt right up with the 54' bell housing.
https://www.flickr.com/photos/advance-design_parts_co/8129099972/in/set-72157631867396207