In half tons(C10),the 3.07 was the economy six option, 4.11 was usually used w/3 spd/OD, 3.73 is the most common. The code should be stamped on top of the pass side axle tube.

Last edited by 64fleetside; 11/07/2007 12:27 AM.
My \'64\'s in the Gallery
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1964 C10 Custom Cab 350/700R4
1964 Suburban 350/700R4
1979 Ford F350 4x4 400/c6