I made the swap in my 1964 L-320 about 2 months ago to a 3.70 and I am thrilled with the results. I cruise all of time on the freeway at 70MPH with plenty of power to go.......will accelerate up to 80+ with ease. I must add that this is on flat ground and the SoCal freeways. Now 1st gear is actually usable. I do have a good set of 4.88 gears left over form the swap with about 45,000 miles on them that I will be selling soon. I also have a complete parts truck we will begin disassembling very soon.......sorry no hubcaps.
Brian