Dan did a good job of deciphering the serial number, but this info from the 1955.2 to 1960 GMC Master Parts book shows a little more.

Your model 414 has a 172" wheelbase, one of 5 wheelbases available with the 41x model. It was equipped with a 270 cubic inch six cylinder engine. It would have either a Timken H100 rear end or the optional Eaton 2 speed electric rear end. The standard transmission was the venerable SM420 four speed with an option for a Clark 205V five speed.

The 4xx series truck's standard electrical system was 6 volt positive ground with an option to have 12 volt negative ground.
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Last edited by Bill Hanlon; 01/07/2024 12:20 AM.
'57 GMC 102, Original 347 V8, HydraMatic, 3.08 rear gear, added A/C, disk front brakes, HEI, AFB carb, '98 Honda Black Currant paint. T-boned and totaled 10/12
'52 GMC 152 Stake Bed, Original 228, SM420, added A/C, HEI, disk front brakes, '67 Chev 3.55 rear gear. Gets used as a real truck.