Mike - I'm not sure what "sources" you're referring to, but the LCFs are "Big Bolt" trucks (1-1/2 ton and up) and those gear ratios you just mentioned were not available for the big trucks. In fact for 1959 the only ratios listed being offered for the 1/2 ton trucks is a standard 3.90, and optional 3.70, 3.38 and 3.92 Posi-track gear sets. None of the 3 ratios you list were available in Chevy LCF trucks for 1959, with or without the optional Powermatic as that transmission was only available for the "Big Bolts".
As far as your understanding of the affects of each of those ratios for engine rpm and acceleration, your not wrong. There's just no connection between those ratios, that were all single speed axles in pickup/panels/Suburbans and the Powermatics and "Big Bolt" single or 2-speed axles.
With all that being said, I'm going to move this thread to the
Driveline forum as that's the best place to continue discussing transmissions and rear axles.
