The 55 and 1/2 thru 59 all had same triangle shaped cluster with 4 across the top with the speedo in the middle. the lower half of 55 (they split the year with two different models) had the same gauges as previous years.
So I am sure its correct. That rear end ratio will help because there are couple different ratios you see on these trucks. and this stuff happens if it has been replaced or the trans has. Since you said your gear teeth on trans side was metal, both the driven and drive gears are matched sets. you cannot change one without changing the other normally in that style. but will know more when you get us more details on the trans. All mine have been automatics so some of the other guys will have to help you out on where to look on the manual ones.
