One issue: In the spiders (mine is a 67 Duetto) there is little vertical room in the engine bay. I always had trouble with the engine+trans unit getting the end of the tx out. The problem was the stub of the gearshift lever "just" hitting the body's bell housing. I always had to twist the engine unit to get it out.
After too many removals, I finally decided to just pull the stub. While you're removing the interior parts of the shift lever, just unbolt the four 10 mm nuts on the side of the tx tower and pull the pivot/vent housings. You don't actually need to remove the lever, just let is slide down a bit; it only needs Ĺ inch or so to clear the body.
BTW - remember to unbolt the ground strap from the top of the clutch bell housing to the upper body. You can pull the engine without doing this, but it does make a mess of things.
That and a $99 HF engine hoist is all it takes to pull the whole thing.
Remember to get the drive shaft u-joints aligned properly on reassembly. Inspect (and almost always replace the rubber donut - it cracks pretty easily. I replaced mine with a modern (german) one now available from the usual suspects (needs proper spacers). Much stronger.