The end of the 4.3 S10 pickup in 2004 was a death knell for many of the mini truck scene. That Chevrolet would no longer support the 4.3 liter engine platform meant that very soon, aftermarket manufacturers would switch gears and begin production of speed parts for the new I5 engine produced for the Colorado. Sure, the new truck has plenty of guts, but there’s just something about the S10 that is utterly undeniable, particularly when outfitted with the sizable 4.3L V6 engine.
The 4.3 V6 engine in the S10 was based on the 350 engine block, incorporating the same pistons, rods, and rotating assembly as the bigger engine, just shorter. For over the top 4.3 engine builds, it isn’t unusual to see engine gurus utilize engine kits manufactured for the 350, keeping two of everything in reserve in case something breaks. There are a handful of (relatively) cheap modifications, however, that you can perform on your S10 truck that will take the 4.3 liter S10 from powerfully stock to screaming. The combination isn’t complicated- more air, more fuel, more exhaust, and it adds up to more power.
The Chevrolet S10, even when fitted with the 4.3 V6 engine, and in Xtreme packages, was fitted with only a single exhaust tube. No dual exhaust was made by the factory for the S10 pickup. For customizers, take a cue from the Camaro. Not only can you improve the sound of your S10 4.3 by swapping the stock exhaust for a dual exhaust unit, but you also have the opportunity to build the rest of the engine from the ground up.
Start with a set of aftermarket headers. Chevrolet did a find job of making headers that work, but you’ll want some headers on your truck that’ll work overtime. JBA and Headman both produce effective exhaust headers, and the kits aren’t too difficult to install.
With the headers installed on your 4.3, the next stages of the new dual exhaust system are as follows: Exhaust cutouts (manual or electric) catyletic converters, crossover pipe, muffler then tailpipe. Use the crossover to balance the exhaust tone and it’ll sound better in the long run, even if it’s a bit more difficult to install right now.
Bumping up the power of your 4.3 S10 requires feeding more air into the engine. Practically any cold air induction kit will work in place of the stock air box, just try to avoid throwing together a homemade version. The S10 4.3 intake has two sensors that are required if you don’t want to be staring at dashboard indicator while you’re driving: the intake air temperature sensor and the MAF, or mass air flow sensor. Remove the MAF sensor and you’ll see a little screen inside. Carefully remove this screen with a screwdriver. With a conical air filter fitted to the intake, you don’t need it, and surprisingly enough, it just restricts the flow of air through the intake.
While you’ve got the air intake off, there is one additional modification you can perform to the intake, perhaps the cheapest so far. A throttle body spacer doesn’t do much for the 4.3 V6 by itself, but when combined with the exhaust and intake upgrades, can make a significant impact on the power curve of your S10 truck. The throttle body spacer installs between the throttle body and the intake manifold, but be warned. The installation of the throttle body spacer and the cold air intake together mean you don’t have room under the hood for the hood- in other words, the hood won’t shut. A cowl induction hood will solve this problem, however, and really, it should have been one of your first S10 modifications, anyway.
Finally, all that air and all that exhaust without the fuel to back it up is going to make the S10 V6 run lean. It’ll run hot as all get out unless you install some larger fuel injectors. One word of caution: Upgraded fuel injectors are very hard to find. The stock units flow at approximately 19 pounds/hour, so look for units which can push 22 pounds/hour to match the upgrades already performed on the truck. CPI injected trucks, however, are as yet out of luck. Please leave comments if you’ve discovered better flowing CPI injection units out there.
Modifying the 4.3 L S10 pickup can be cheap, that is, cheaper than a supercharger or installing a V8, both of which can quickly and easily run into the thousands of dollars. One thing’s for certain, however, modifying Chevrolet’s small pickups and Blazers will still be loads of fun, even after the Colorado has long since disappeared and the next replacement comes along.