After a thorough inspection and deep cleaning, the engine was put back together and, since I had a lift in my garage at the time, installed the easy way. First, with the engine on the stand, we bolted on the engine mounts and subframe.
Then we put the engine on a rally tire and installed the clutch and flywheel. Can't remember precisely which one we used, but it was some clever Jim Wolf concoction that used an aluminum flywheel and some 350Z parts to make a totally benign, streetable clutch that can handle way more than we'll be doing to it.
Finally, the transmission was installed, the whole contraption balanced back on the tire, and the car was lowered in place. Why is this so much easier than stuffing the whole thing in through the top? Simple: This is how it was designed to be installed at the factory. All the hard-to-get-to fasteners around the turbo and steering rack and under the manifolds are all easy to get to when the drivetrain is sitting on a rally tire. Once the car is lowered into place, it's just a few bolts connecting the engine and transmission crossmembers to the car.
Another potential cooling system issue was an A/C condenser clogged with gunk. SR20s aren't known for good cooling performance in the first place, but expecting it to shed 50% more heat than it was designed for through an intercooler that isn't supposed to be there and a wall of grunge is just asking for trouble.
You want air conditioning with your Silvia? Here's a toothbrush…