You may run into some issues with changing the gear ratios in the differentials, mainly the rear, if they are the factory axles. The front shouldn't be too much of a problem, as it is the closed knuckle Spicer/Dana 44. Plenty of gear choices available for that one. However, the rear will be an HO52. There are no aftermarket gearsets avaialbe for that differential, the only option is to find the third member from a '68-'72 C20, usually with a 350 and automatic, which has the 4.10 gear. The only other choices are a 4.56, which is most liley what you have, or a 5.13, usually found in 1 tons.
