What is a stroker engine?

A stroker is:

An engine that has had the length of the pistons travel extended through a machining operation or:

In the case of a small block Chev you can fit the crank shaft from a different displacement engine into a block and create a stroker.

The 383 stroker is a common one. Use a 350 CID block and a 400cid crank and conecting rods to get the 383 cid with out the reliability and life shortcomings of the 400 block.

It is also possible to de-stroke an engine to get percise displacement for racing or special operational requirements.