You can use a trolley jack under the gearbox, this will level everything out as it goes in. Done this heaps of times with a block and tackle, one person job.

Well I guess it also comes down to whether you have a crane or a block and tackle.

I use an average sized engine crane and you certainly can't get that much of an angle on it (practically) at that height without it slamming into stuff and carving up the engine bay.

If I could get a complete 4AGE and W58 gearbox in and out as a unit without scratching anything up, I'm pretty sure you'll be able to do it with an A series...

I just had the pleasure of installing both the motor & trans then pulling & reinstalling the motor due 3 leaking freeze plugs & a oil pan gasket that leaked like a sieve. I originally had the motor in first then installed the trans which went in pretty well, minor wiggling to align the splines.

2nd time around I left the trans in & gambled, pulled the motor, reinstalled it - everything went smoothly. Aligned itself quite easily but I think others are right unless theres lots of room under the car its more difficult.

I've done it both ways, & the advantage of lining up the clutch & being able to get to all the bolts properly outweighs the extra care needed. I usually put the REAR wheels up on wheel ramps or stands, so the back of the box doesn't have to go down too far to go in. It's a bit of a squeeze doing up the g/box crossmember bolts, but really easy for doing up the tailshaft bolts. All the bolts in the engine bay can be done up from the top, or you could just remove the wheel ramps.

I like to remove the engine crossmember and detach steering linkages from passenger side. Then put engine and gearbox on the crossmember with it lying on the shed floor. Do this underneath the engine lifting point if you are using a block and tackle. Then roll the car forward and lift the front of the car over the top of the engine using block and tackle. Once engine is aligned to its resting place in the engine bay, attach the lifting chain to engine and gearbox through the engine bay and lift into place.
While lifting engine put a trolley jack under gearbox crossmember to lift the gearbox. Use a rope through shifter hole to pull up gearbox onto jack.

This is the best way to do a ca18 install without an engineering degree.

I have only installed them seperately once and it was a lesson learned. Every other time i have done it with the car on stands and it has been a breeze.

i install my ca18det and ca box as a unit as long as you take it easy its not too hard makes it abit easier if you get a mate to help
it would be a heap easier to install an a series with the box attached

Yes. I've always thought it was easier to install the engine and tranny as a unit. Less crawling around under the car. Less crawling is getting more important as time goes on. Seems like the floor is getting further away as I get older...

I have done it with the car on ramps and stands. As Chris suggested, there is not much room to swing the engine/gearbox. I find it easier to just install them seperately...