1953 3100 1/2-ton with 216ci
the 216 is numbers matched to the year, i have the factory three-on-the-tree transmission, with the factory closed-drive shaft and the rear differential carrier has all the mounting and brake line hardware to tell me that it's factory..
ALSO: my tires are 235/60/15
however, i've recently replaced my speedometer with a new one (cable as well) from classicparts.
on my last couple road tests, my speedometer is telling me i'm topping out at ~52mph.. i immediately knew something was up, since my old 216 is only getting 90psi on all cylinders, and it's just nonsensical to think i could get that speed with all factory gear.
so i got a speedometer app on my phone, (checked it for accuracy in a newer car) and checked my speed. i'm actually going 5mph slower than the speedometer is telling me (at all speeds).. the odometer is off by roughly +2/10ths of a mile as well. all the basic "calculate your rear axle ratio" tricks require an open driveshaft, so i'm wondering if anybody knows another way for me to calculate my gear ratio without popping open the carrier?
i'm guessing my gear ratio would have to be in the 3's:1 area, right? i'm supposed to have 4.11:1
TLDR; factory engine, trans and brand new speedo+cable..speedo is +5mph, how do i figure out my gear ratio?
Last edited by gmtjr; 03/23/2014 1:16 AM.
