I have read the post's on interchange parts. Very helpful info. However I'm interested in converting my 4 lug 72 comet to 5 lug retaining (for now) the drum brakes. Will 5 lug front parts go on the 4 lug (bolt on)? Will 5 lug axles replace the 4 lug one's ? My diff. does not have a cover on the back. Any help is appreciated.