I just did this job on the weekend, but I removed the engine and trans together from both cars as there was a lot more work than just swapping transmissions that needed to be done at the time. Yes a 740 tranny will be fine, just make sure you get an AW not the ZF that a few 740s had. They are visibly different. Your best bet is as follows: First pull the drain plug & drain the fluid. While that's draining, get under the hood, disconnect the kickdown cable from the throttle spool. Then undo the 2 nuts securing it to the bracket on the manifold. Tuck this down into the transmission tunnel, gently so as not to crack the housing where it enters the transmission. Remove the dipstick or you'll break it. Remove the disttributor & rotor, to give extra clearance from the head to the firewall. Inside the car, undo the wire for the OD where it enters the shifter housing through a rubber grommet facing the front of the car. Usually, this wire gets cut off under the car then spliced back together, that's fine if you can't get it out & if time is limited, just cut it off as long as possible from the solenoid. Unbolt the driveshaft, you may need to also unbolt the center suppport bearing and slide the entire front shaft out. Unhook the shift linkage (just circlips). Unbolt the cooler lines from the passenger side of the tranny & bend them out of the way. Now, unbolt the tranny crossmember and as you do this the engine & tranny will drop. The head will wedge against the firewall & stop it from dropping further. You need to remove the bell housing brace, 4 bolts straight up into the block & 2 forward through the bell housing. Now you can get at the torque convertor bolts, there are 4 & they're tricky to get to. Rotate the engine with a socket on the crank pulley bolt (or pull the spark plugs & rotate by hand) to get at each of the TC bolts. It's time to remove the bell housing bolts and the 2 that hold the starter in also will (usually) have nuts on the starter side. After the bolts are all out, gently pry the tranny free of the 2 mounting dowels on the block & drop it down. BE CAREFUL NOT TO LET THE TORQUE CONVERTER SLIP FORWARD OUT OF THE TRANNY! It is very hard, sometimes impossible, to properly reengage it to the pump shaft splines. Bend an old wrench a bit & secure it against the TC by means of a nut & bolt through one of the bell housing bolt holes, to hold it in place. And no the tranny can't be removed from the bellhousing without first removing it from the motor, and removing the torque converter, so don't try that approach. Pretty straightforward but a real PITA to get at some of those bell housing bolts, take plenty of long wobble extensions and a u-joint or two, and a good-quality 17mm & 19mm socket, preferably thinwalled. Good luck!
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Chris, Dartmouth NS Canada 70 M-B 280SE, 83 245DL, 84 244 turbo, 90 780 turbo, 92 VW Golf, 90 740 Rex/Regina