I put the same unit into a 59 Suburban, and had a lot of tire-clearance problems with the rear wheel openings. The axle was about 2" wider at the wheel attachment flanges than the original rear axle. If you're running a flatbed instead of a stepside bed, the width difference might not be apparent, but I believe the early 50's track width was somewhat narrower than the 55-59 models.
Jerry

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