The 5/8" inch depth info can be found in any late 50's early 60's Parts Book under the "Installation Instructions" section which is found on about page 100 (after the illustrations).
Hope this helps,
Mike B
Mike Boteler
1956 Chevy 3100 Resto Rod 1952 Willys M38 Army Jeep 1983 Jeep CJ7 Laredo 1984 Jeep CJ7 +++++ Silver Spring, MD
