I'm not familiar with the 55, but the 48-53 1 tons use same brakes, and in fact same rear axle altogether, for the singe and dual wheel trucks with one exception of wheel stud length.
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I have to admit to making an error, the rear brakes are the same for dual and single on the '55, 12" in front, 14" in the rear.
The 8 x 180mm bolt pattern I mentioned was for '11 and up Chevrolet and GMC pickups, vans still use the 8 x 6.50" pattern.
