Garageguy6078,
Since your '53 Panel truck repairs involve primarily the cab front body sections and floor (from your description), you may want to ask this question in the
Paint and Body Shop forumYour questions apply to all such truck cab sections, with little variation until you start moving to the rear beyond the door openings.
Here is just one of many conversations about what you are asking about found using the
Search the Site link in the left margin of the page:
https://www.stovebolt.com/ubbthread...98507/re-cab-rust-repair-what-order.htmlBetween re-asking your question in the Paint and Body Shop forum, and using this tool to further search for previous conversations, I think you will get more response and have a good bit of info to help decide on your plan.
Another very necessary and useful resource you should have is a Factory Assembly Manual. The GM approved reprint I have is titled 1947-1954 TRUCK Factory Assembly Manual. This book has detailed truck assembly sheets for most every section of our trucks, along with diagrams that provide specific body measurements as initially designed for assembly specifications at the factor. These reprinted books are available form many sources. Do a web search and you should be able to get one in hand fairly quickly.
One other suggestion - take a look at other Project Journals for folks with 1947-55.1 Advance Design trucks. Many of them have probably done what you are looking to start and their information and pictures they have posted will be of help too.
Hope this is of some help in moving your project along.
Dan

EDIT: Seems Kevin beat me to the posting punch - lol. Hope all we have noted is helpful!
