4 The TBI unit used for the project is simply a salvage- yard part scavenged from any of the millions of GM trucks built from the mid ’80s through the mid ’90s—including the 4.3L V-6, the 5.0L and 5.7L small-blocks, and even the 7.4L big-block (the latter will require a larger-bore adapter plate). This one came from a 4.3L S-10, featured a pair of 45-lb/hr injectors, and was purchased at a pull-your-own yard for $35. It’s important to make sure the unit still has the throttle-position sensor (TPS) and idle-air control sensor (IAC). A couple of coolant sensors are required, too, so be sure to grab them from the same donor engine. For safety’s sake, it’s also a good idea to replace the TBI unit’s gaskets and seals.