When the engine in a classic vehicle is in need of an overhaul or an upgrade, the question many people ask is should they rebuild their original engine or replace it with something more modern. There is also the option of installing a late-model computer-controlled fuel-injected engine, but most of these just don’t fit with the image of a classic when you open the hood. No matter what your or your customer’s choice is, you need to be sure the selected package matches the way they drive.