For a quick fix, you could put taller tires on the rear. It won't be a world of difference, but it should be notice-able. I put extra tall tires on my '72 C-10 to help with the 3.73's and it seemed to knock it down to about 3.63.
Bill
'60-'72 Chev/GMC Fan GMC 9500 Fan Detroit Diesel Fan
