Dito 52Carl. My 51, 3600 has 4.10s with a .72 5th gear wct5. The driveshaft shop had no problems making a 4"dia 1 piece driveshaft.
The gear ratios work out great for my needs, on flat ground I run 5th, in the hills not so much but that's what the other 4 gears are for.
Good Luck,
RonR