This guy is right. D, B, and to a lesser extent, K-series parts were - and ARE - in very, very high demand due to ease of installation, swapping, and durability. Oh yeah, and the secondary market for racing/show cars don't care much if the parts are stolen at all. They expect it, generally.

Any D-series motor bolts directly into any car with D-series engine mounts, and same is true for B/K series cars. Putting a B-series engine into a D-series chassis is pretty simple too, just requires some drilling and new engine mounts. Not a direct bolt-in but not difficult either.