Different generations of LS based engines came with different styles of throttle body. They got better in time and more efficient and easier to tune. Some have an IAC (idle air control) valve in the throttle body itself that controls idle airflow. The newer blades do not, they control idle airflow by just tipping the blade to a commanded point.
What this means to you?
This means that you have multiple options on the throttle body for your application. The earlier models are a three bolt type, meaning they bolt to the intake only using three bolts. The newer generation throttle bodies are 4 bolt. Different vehicle also have different size throttle bodies, and many aftermarket companies sell even bigger throttle bodies like the 102 mm. ICT Billet makes all kinds of adapters to make pretty much any throttle body work with your application. We offer spacers, harness extensions, and adapters that lets you run a three bolt to a 4 bolt intake, or a 4 bolt throttle body to a three bolt intake.
Feel free to Contact Us if you have any questions!