You might want to find out what gears it now has. If it was a hot rod it may have 4:56 gears, in which case a 3:08 would make a difference.
Most of the time it is in the transmission with a 1 to 1 for the top gear. Without overdrive, all old trucks were geared low.
In the tech section there is a link to figure final speeds based on tire diameter and gears. I changed the xls worksheet to add for an overdrive in the tranny.
There are a number of websites that give the diameter of different tire sizes, and their RPM ie mine equals 29.9" and 791 revolutions per mile. That way you know exactly what tranny, rear gears and tires give what speed at a given engine RPM.
Last edited by Jon_S; 08/11/2011 4:02 AM.
