Same length for same model axle.
Some much later model axles do have shorter spindles, usually when equipped the disc rotors that slip over the hub, not behind the hub.

Can you clarify your question, and what do you mean with the 5/8" measurement?

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
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"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-