Chevy Bolt On Parts - Bang For Your Buck
It makes the hot-rodding world go 'round. The aftermarket develops parts; we purchase these creations and bolt them on to our rides. When things go right, our Chevys churn out more power, move faster, turn harder, brake shorter, and in general perform better than they ever did when new. As we began this bolt-on examination, we decided to do two things. One was to pick bolt-on mods that, while maybe not the cheapest, are cost-effective. In other words, we endeavored to pick items that deliver a return for your time and money. And our second course was to ask the various manufacturers for documentation. Back up the claims. Show us. Hard numbers were preferable, but we went with anecdotal evidence where need be. Here are our findings. We hope you find them helpful, and happy bolting!
It's certainly great to build a slick, fast piece of Chevy muscle, but isn't it equally great when the ride you've spent so much time on stops on a dime, too? It's a performance issue, and even more so a matter of safety. Many of our favorite musclecars came with woefully inadequate drum brake systems, so upgrading to modern components just makes sense. Master Power Brakes carries a number of complete power front disc kits for Chevelles, Camaros, and Novas (for about $850). There's also the 11-inch rear drum upgrade, which we installed and tested in July '04 ("Drumming Away"). This $400 drum setup cut 26 feet off our stopping distances. Then there's Stainless Steel Brakes' Quick Change kit, which changes stock front brakes to a twin-piston caliper and slotted rotor. In testing this quick and easy mod on a small-block-powered '67 Nova SS wearing 15-inch wheels and tires, SSBC reportedly cut the Deuce's 60-0 stopping distance from 160 feet to 110 feet. Plan on spending around four bills for this one
Bolting in a new mass airflow sensor is a quick and easy way to increase horsepower in a fuel-injected car. An aftermarket MAF interfaces with a car's ECM as the stock piece would, but moves much more air-60 percent more, according to Granatelli Motorsports. Then again, airflow is only part of the story. The sensing element in a MAF provides a signal to the ECM that influences fuel and ignition control. In an aftermarket piece, this sensor is calibrated to maximize performance. So what does that do for you? According to GMS, throttle response and mileage are improved. Oh, and power gains come in at 21 hp over stock on an LS1-powered Camaro, and even a bit more on LT1 versions. Plan on spending about $300.
Your vintage Chevy's suspension system is another area where a little modernization pays big dividends. Switching to poly-urethane bushings can certainly tighten a veteran Chevy up; a system like Global West's Negative Roll setup brings hi-po geometry to the street, creating much improved handling manners. Expect to pay as much as a grand for a set of upper and lower control arms, but expect to feel the difference. Of course, even something as simple as a shock swap can improve your ride's handling characteristics. Swapping out standard gas shocks in favor of adjustable QA1 Street Stars can improve skidpad performance by .06g, and also increase slalom speeds by 2 mph-again, you'll feel this on the street. A set of four should check in around $600. But if your heart's at the track, Competition Engineering three-way adjustable drag shocks can drop your 60-foot times by .0070-.0090 second. Forty bucks apiece will do the trick.
Replacing a restrictive exhaust system is one of the quickest ways to pick up more horsepower, and this popular mod usually has a double payoff: Your ride ends up sounding better, too! Flowmaster's 3-inch Delta Force system for A-bodies showed increases of 14 hp and 12 lb-ft of torque on a 454-powered Chevelle, and as our own Kevin McClelland demonstrated in our June '04 issue, a well-engineered system is very efficient. While tuning a 572 crate motor wearing dyno headers, installing a 3-inch dual exhaust and Super 40 mufflers cut peak power by a mere 3 hp. And speaking of headers, Stainless Works' teamed their new '98-02 Camaro cat-back with a set of their new headers on a '00 SS, and the dyno showed gains of 24 hp and 12 lb-ft. These systems go for $500 to somewhere around $650.
572 w/dyno headers
651 hp at 5,700+Super 40 mufflers
648 hp at 5,700'71 454 Chevelle
298.2 hp at 4,500
312.5 hp at 4,500+Delta Force exhaust
373.6 lb-ft at 3,700
386 lb-ft at 3,800'02 Camaro SS
340 hp at 5,581
364 hp at 5,781+SW after-cat & headers
358 lb-ft at 4,131
370 lb-ft at 4,331
As with so many of the bolt-on components we've discussed here, headers are an excellent way to improve performance-when properly matched to an engine. Larger tubes may mean more power, but not if gas velocity drops. Case in point: the "Header Ho-Down" in our April '04 issue. We tested a Smeding Performance 383 crate motor (rated at 440 hp and 440 lb-ft), fitting four different headers ranging from 1 1/2-inch FlowTech shorties to 1 7/8-inch Hooker long-tube pipes. As you can see, horsepower increased, but torque began to fall off with larger primaries-especially in the midrange. Choose carefully. Prices range from $250 for the FlowTechs to just less than $600 for ceramic-coated Hooker long-tubes.
1 1/2-inch
435 hp at 5,600 rpm
461 lb-ft at 4,1001 5/8-inch
441 hp at 5,400 rpm
468 lb-ft at 4,4001 3/4-inch
449 hp at 5,600 rpm
467 lb-ft at 4,500 rpm1 7/8-inch
451 hp at 5,700
459 lb-ft at 4,400
Throttle Body
Bigger could be better for fuel-injected motors, too. On the other hand, bolting on a new throttle body isn't just about increased airflow. It's also about smoother increased airflow, creating more power and better throttle response. TPI Specialties has a couple of LT1-compatible goodies. The 52mm unit (900 cfm) is a rebuilt factory casting that has been rebushed, bored out from 48mm to 52mm, and fitted with a TPIS air foil. We're told you can plan on 15-plus extra horsepower on a stock motor. Then there's TPIS 58mm billet throttle body (1,100 cfm), which features ball bearings on the shaft and a built-in air foil. While it can be used on a stock motor, it's also well suited to big-inch applications. Then there's the new 90mm throttle body for the LS6 manifold-that's right, an LS2-sized butterfly, adapted to fit the Gen III motor. Look for another 8 hp from an almost-stock LS1. The 52mm piece comes in at just under $300; the big boy goes for $500, and the new 90mm unit for $499 (with exchange).
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-cfm</br />409 hp at 5,500</br />440 lb-ft at 4,300600-cfm</br />438 hp at 5,700</br />458 lb-ft at 4,400650- and 750-cfm</br />444 hp at 5,600</br />461 lb-ft at 4,300830-cfm</br />449 hp at 5,700</br />462 lb-ft at 4,400
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
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.
Intake Manifold
There are many advantages to swapping intake manifolds. Lighter weight and better airflow into the cylinder heads are certainly chief among them. Of course, this is another piece that must be matched to the rest of your combo. Displacement, cam and head selection, and planned rpm range are all factors to consider. In fact, these parts are so dependent on one another that companies like Edelbrock like to sell manifolds as a "Power Package" with a cam, heads, and even a carb. That being said, you can look for power gains of 20-30 hp with a wise manifold selection, and prices start as low as $100.
Underdrive Pulleys
OK, we know these kinds of things usually come in 10s, but what can we say? We came up with 11. Underdrive pulleys are a relatively quick and easy way to free up some horsepower. March Performance tells us their Performance Series kits usually increase power about 12 hp. The Power & Amp Series pick things up by 10 or 11 ponies and allay fears about inadequate charging by spinning the alternator faster. A pulley kit starts at about $150, while full serpentine conversion kits are about double that.

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