msgjd
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Nothing more than the positioning of the existing OEM parts.
Referencing the M39-series 5-Ton gassers (M139, M51, M52, M54, M62 etc) , there are early-mid 1950's online gov't pictures featuring new gassers with upper-quadrant headlights.. This was quite surprising to me since I had previously believed gasser 5-Tons (and gasser deuces) were all originally lower-quadrant.. Throughout the 1960s while watching long convoys pass thru town, and during my own service time within the following 3 decades, all Deuce and 5-Ton gassers were lower-quadrant .. Apparently that was not always the case, since now seeing those old pictures...
I had also previously believed the upper positioning was done for visual uniformity after the advent of the A1's and A2's whenever a gasser got rebuilt into a multifuel A2.. But that is also incorrect .. Not all gassers nor all gasser/multifuel conversions got their quadrants flipped during their time in the inventory regardless of what I had seen during my own enlistment..
Why there was ever a difference in positioning is beyond my pay grade although I usually had noticed an improvement in Blackout Drive illumination (brightness) with upper-quadrant headlight positioning although the light did not spread out as far as the high ones on lower-quadrant trucks..
So here's the skinny :
Right-hand (passenger)
Lower Quadrant: Note the spacing of the upper/lower openings, and the removable crossbar is flipped upwards
Upper Quadrant: Note different spacing of the upper/lower openings, and the removable crossbar is flipped downwards
Left-hand (driver)
Lower Quadrant: Note the spacing of the upper/lower openings, and the removable crossbar is flipped upwards
Upper Quadrant: Note different spacing of the upper/lower openings, and the removable crossbar is flipped downwards
To perform the change, all you have to do is remove the 6 bolts from each of the two rectangular mounting boxes and take them out of the truck .. Then remove the 4 bolts from the B/O Drive lamp mount and also the Headlamp boxes , Invert the rectangular mounting boxes and reinstall what you removed .. Then put the two sets back in the truck.. Also, you will need to remove and rotate (flip up or down) the two horizontal crossbars.
Referencing the M39-series 5-Ton gassers (M139, M51, M52, M54, M62 etc) , there are early-mid 1950's online gov't pictures featuring new gassers with upper-quadrant headlights.. This was quite surprising to me since I had previously believed gasser 5-Tons (and gasser deuces) were all originally lower-quadrant.. Throughout the 1960s while watching long convoys pass thru town, and during my own service time within the following 3 decades, all Deuce and 5-Ton gassers were lower-quadrant .. Apparently that was not always the case, since now seeing those old pictures...
I had also previously believed the upper positioning was done for visual uniformity after the advent of the A1's and A2's whenever a gasser got rebuilt into a multifuel A2.. But that is also incorrect .. Not all gassers nor all gasser/multifuel conversions got their quadrants flipped during their time in the inventory regardless of what I had seen during my own enlistment..
Why there was ever a difference in positioning is beyond my pay grade although I usually had noticed an improvement in Blackout Drive illumination (brightness) with upper-quadrant headlight positioning although the light did not spread out as far as the high ones on lower-quadrant trucks..
So here's the skinny :
Right-hand (passenger)
Lower Quadrant: Note the spacing of the upper/lower openings, and the removable crossbar is flipped upwards
Upper Quadrant: Note different spacing of the upper/lower openings, and the removable crossbar is flipped downwards
Left-hand (driver)
Lower Quadrant: Note the spacing of the upper/lower openings, and the removable crossbar is flipped upwards
Upper Quadrant: Note different spacing of the upper/lower openings, and the removable crossbar is flipped downwards
To perform the change, all you have to do is remove the 6 bolts from each of the two rectangular mounting boxes and take them out of the truck .. Then remove the 4 bolts from the B/O Drive lamp mount and also the Headlamp boxes , Invert the rectangular mounting boxes and reinstall what you removed .. Then put the two sets back in the truck.. Also, you will need to remove and rotate (flip up or down) the two horizontal crossbars.
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