The dana/ spicer were primarly used by GMC while 3/4 & 1ton Chevy trucks (usually) ran the Eaton regardless of what it had for a suspension, but prehaps with the exception of the optional 4.11 ratios. All of the GMC trucks from the 60's and early 70's that I have seen with the Eaton rear were 10K GVW trucks with the 5.14 ratios.
