Automobile engine replacement
A crate engine is a complete replacement internal combustion engine for a car, generally a fairly high performance engine. What distinguishes a crate engine from other replacement engines is that it is a complete, pre-packaged, new-build solution, already packed in a shipping crate (hence the name) ready to be bought off-the-shelf. The crate engine provides a quick, simple, guaranteed motor. Many are built up by the original equipment manufacturer, while others are assembled by specialist firms.
This is in contrast to the traditional method of obtaining a performance engine, which is by building it from components or having such an engine custom built by a specialist. The best custom-built engines can outperform a crate engine, of course, but the cost in money, time, and uncertainty can be high.
All of the American "Big Three" - Chrysler, GM and Ford - sell crate engines of various specifications. A number of independent engine builders sell such prebuilt units also.