Ted, I used an open drive on our dragster when it had the 39 rear end in it, this is VERY easy to do, cut the end off the torque tube that mounts onto the diff,machine it about 25mm long from the flange,get a drive shaft flange from the wreckers to suit the driveshaft you are going to use,machine that to fit a 6 spline coupler in,weld them, then machine the od of the couple just to clean up to run a seal on,then machine the inside of the shortened t/tube to fit the seal in. fit the flange with the 6 splined coupler on after the flange and pin it to the pinion shaft,
No worries,
If you want a open drive crownwheel and pinion let me know.my mate has a couple.
Lawrie