I believe Kevin is right. Although the factory did offer overload springs for your ‘53, they don’t look like that. My ‘52 3100 came with overload springs and they appear to be factory, listed on page 434 of the 1929-1954 Chevrolet Master Parts and Accessories Catalog under 7.503, Spring Assembly, Rear section. 47-54 Util 6 leaves (Aux Springs) Part 604934.
Phil Moderator, The Engine Shop, Interiors and Project Journals
1952 Chevrolet 3100, Three on the Tree, 4:11 torque tube Updated to: ‘59 235 w/hydraulic lifters, 12v w/alternator, HEI, PCV and Power front Disc Brakes Project Journals Stovebolt Gallery Forum
