Carburetors
The "bigger is better" school of thought runs rampant in our hobby. When it comes to carburetors, however, this isn't always the case. A carb needs to be big enough to give the combustion chambers all the mixture they can handle, but not so big that airflow velocity suffers. We tested a variety of Holley 4150 carbs on a Smeding Performance 383 crate motor ("Size Matters," March '04), which came rated at 440 hp and 440 lb-ft of torque. As you can see from our carb swap-o-rama, matching the carb to the engine combo pays off. Bigger was better-up to a point. At carb sizes greater than 750 cfm, the law of diminishing gains came into effect. Spending that $300-$600 wisely will pay off with optimal performance.
| 390-cfm409 hp at 5,500440 lb-ft at 4,300 | 600-cfm438 hp at 5,700458 lb-ft at 4,400 |
| 650- and 750-cfm444 hp at 5,600461 lb-ft at 4,300 | 830-cfm449 hp at 5,700462 lb-ft at 4,400 |
Nitrous
In the bang-for-your-buck arena, nitrous is king. Of course, we don't mean "bang" literally. Success with nitrous requires an engine that can take the boost, proper installation, and prudent use. That being said, it's not called "horsepower in a bottle" for nothing. For approximately $600, a system like the Zex perimeter plate setup shown here allows the home juicer to bolt on 150-300 hp. Here's a tip from Zex: When shopping for a nitrous system, determine if the stated power increases are measured at the crank or at the wheels. Zex systems are tested at the wheels; the 150-shot example shown here, tested on an Demon-carbureted LS1 fitted with a COMP cam, picked up 154 hp and 187 lb-ft of torque. Now that's a nice return on you dough
Gears
Once you've bolted on all sorts of power-adding goodies, it only makes sense to bolt on something to get more of that power to the ground. Installing lower rear gears is a particularly effective way to increase your Chevy's fun factor and lower its e.t.'s. Stiffer gears accomplish this by getting a motor into its powerband more quickly. Using Reider Racing's online rpm calculator to cook up an example, a Chevy with 3.08:1 gears running a 27-inch tire would turn 2,361 rpm at 60 mph. Bump that up to 3.73:1 cogs, and you're turning 2,860 rpm at 60 mph. That 60 mph arrives in shorter time, dropping 60-foot times in the process. A good ring-and-pinion set costs about $175; an installation kit can run from less than $100 to almost a bill-and-a-half, and having a pro do the swap-which we highly recommend-should cost around $400.