[Christ]

Truly expensive.

From what I've been able to glean through limited reading and images, I don't see that there is a structure that is molded into the plastic, but it appears that there are two structures on the block, a bedplate for the crank which also has the sleeves, and a cap which installs on the block deck, then a matching cap which installs on the lower deck surface of the head, so that when the head bolts are installed, everything (including the composite block) is compressed together.

I have decided through thought exercises that a potentially better design would be to have a bedplate for the crank bearings, with only a small portion of the sleeves attached, and a groove into which the upper deck plate (which now contains the majority of the sleeves) fits. There are two good designs which could be used to mate the upper and lower portions of the sleeves, namely stress fracking, which creates uneven, but uniform mating surfaces, but is potentially timely and not always predictable, and groove/insert, in which one sleeve's ID is widened while the other portion's OD is reduced so that they interference fit together.

The reason I feel this to be superior to what I've seen is that the piston's travel never reaches a certain portion of the cylinder, and that portion of the cylinder is where the two portions of the sleeves could be mated. The sleeves having to mate each piece of the upper and lower plates prevents the plastic from being strained, and ensures that stresses are somewhat evenly distributed between upper and lower deck surfaces.