Hah, I know this one; You can't take just the tail off. Well maybe you could, but you'll never get it back together with the cluster-pin still installed.
The proper way is to unbolt the tail rotate it about 180*, then from the front; drive the cluster-pin out the back until it hits the tail, then rotate the tail a smidge to where the factory sorta provided a little space for the pin to sneak past. Collect the little half-moon key now before it gets lost. Then remove the pin all the way. Now stand the trans on its front, putting the input thru a hole in your bench, (of just figure something out). Be advised that the needle rollers can/will come crashing down on the floor thru the pin-hole in the front of the case, so put an empty 5 gallon pail underneath to catch them; I think there are supposed to be 88IIRC. Reach inside and push the cluster as far towards what would normally be the bottom of the case as it will go. Now the tail will go straight up, while losing the front synchronizer sleeve, and flipping the struts who knows where. To prevent that, you can use one hand to steer the sleeve around the cluster, while simultaneously lifting the whole shebang outta there. And there you have it.
To reassemble it, you have to wash the cluster to be oil free in the tube and repack the rollers in there with grease to keep them in there.
You have to do the same with the input rollers. I forget how many there are in there; I wanna say 17 but I don't think that's right. And I grease the thrust washers to the case so I don't have to chase them around.
To assemble it, the front retainer will have to come off and the input gear slid forward as far as it will go. I stand the case on it's nose again, and drop the assembled tail down while steering the mainshaft nose into the input gear. The 3-4 sleeve has to be slid partially forward just prior to engagement, as it passes by the cluster; and then back to neutral so the struts will keep it up there. It's a bit tricky and some guys try this with the case laying on it's side, bottom up. Yeah good luck with that, IMO, that is even trickier. If you can't drop the tail in there with one hand, (yeah I know it gets heavy) find an assistant to do one or the other. Do not use a hydraulic cherry picker if you value your fingers.
So anyway once you get that mated and you know for absolutely sure that every single input roller is in place, and not one single roller fell into the cavity in the bottom of the input gear, take a breath. (please note if a roller or two end up in the cavity two things can/will happen; 1) there is just enough room in there for one roller. If a second one gets in there, you may never know it on the bench. But the roller will continuously rub on the mainshaft and burn up the nose. and 2) with two rollers missing from their support duty, the m/s will not run on it's design centerline, and in third gear, the incoming torque will separate the gear trains leading to noise and possible shifting issues. So, you may wish to practice this step. You have to be sure, cuz you cannot see. Three will not fit in there and then you'll know it right away. The nose of the m/s is beveled to help)
Now once again rotate the tail piece ~180* to find the cluster pin access port. Pull the cluster into position, and align the thrust-washers. Shine a light down inside and be satisfied to see all the rollers where they belong. Then slide the pin in until it stops, checking the front T-washer is properly on the pin. Then orient the pin so the key fits and drive it home flush with the case only. Now, you did install the gasket previously right? OK so then, without tearing the gasket, rotate the tail to correct orientation and install two bolts at 180* just snug.
Next, lay the trans on it's side with the cover side up. The next part is tricky; you have to simultaneously push the input into the box while indexing the front brass ring onto the three struts, with the slider in it's neutral position. If the slider was moved to the rear during the installation procedure, the fronts of the struts may have popped up, or even flipped out; don't panic! You can put them all back into place without taking it all apart again.It's tricky but doable. Then continue indexing the front brass ring followed by sliding the input gear back until the big snapring halts the progress. Now you can reinstall the front retainer. Followed by the other 4 rear bolts, and torque it all down.
BadaBoom
As to cables; the ends are the same and the exit points are about the same, so IDK why there would be two cables. My auto cable slipped right into place on the A833, no fuss. This is on a 67 to 72 A-body
Have fun