From The Desk Of Michael Copeland:
The GM LS Series of engines is a popular choice for use in almost any vehicle not built with one. Virtually every vehicle GM has built in the last 100 years could benefit from swapping in a LS engine. And why not-GM has built millions of them. They make great power, deliver amazing fuel economy, and are compact and lightweight. Not to mention, with all the factory and aftermarket support, these engines can be built to meet almost any requirement. Here are some of the "most common" topics that come up when discussing LS swaps.

•Generation Identification
Currently, there are GEN III and GEN IV versions in the LS family. The easiest way to determine which version you have is the location of the cam sensor. GEN III engines have the cam sensor located in the block at the rear of the intake manifold. GEN IV engines have the cam sensor located in the front cover. GEN III engines have 24x crank sensors and GEN IV have 58x. The 24x sensor has a black connector and the 58x has a gray connector. Engine controllers must be matched to this sensor or the engine will not run. Both cam sensors will work with either crank sensor, but the connector has to be repined to match the engine controller.

•Engine Size
All LS engines, from 4.8-liter through the 7.0-liter, are the same external size. This is true for even the maximum horsepower versions from GM, including the Supercharged LS9 and the LSX 454 Crate engine. All production LS engines have the engine size cast into the block. There are different power levels available in LS engine sizes, and the only way to identify which version you are looking at is to check the VIN number stamped in the block.

There are aftermarket blocks available (Dart, RHS, World Products), both in short and tall deck versions. GM Performance Parts has both a standard and tall deck LSX iron block. These blocks allow you to build LS-based engines all the way to past 500 ci. With some of these aftermarket race blocks the deck is higher, but the rest of the block shares common dimensions with the production LS engine.

•Engine Mounts
All LS series engines have the exact same mounting bosses for the engine mounts. This makes swapping any LS for another LS a bolt in. There are many aftermarket companies making adapter mounts to install a LS into almost any vehicle made. While most share the same basic design, there are some differences. Make sure you use the mount the adapter manufacturer recommends, and install it per the instructions. Not following their directions can make the engine sit in a different location, and this can make other components like headers or oil pans difficult to install. Before purchasing additional components, you should contact the mount manufacturer to determine which components were used in the design of their mounts. Many of these mounts place the engine in slightly different locations and, unless you verify which parts work with their mount, they might not fit without modification. Also note that some iron LS blocks have undrilled bosses and need to be drilled to mount some accessories.