Top 10 Budget L98 Bolt-Ons RICHMOND RING AND PINION GEARSET
The vast majority of L98 F-bodies came off of the assembly line with highway-cruiser axle ratios. An upgrade to a 3.42 or numerically higher gearset will yield, dollar for dollar, the best performance increase you can get. Be sure to match the gearset to your engine rpm range, and beware that some L98 cars had the dreaded Australian 9-bolt rear: gears will be much harder to come by for these. Price includes the installation kit--and sticky tires might be needed too.
THE CATCH:
Gear noise increase; fuel economy decrease
EASE OF INSTALL:
Difficult
WEAR AND TEAR:
Heavy
APPROX. HP GAIN/ET REDUCTION:
60 HUNDREDTHS
COST:
$280.00
COST VERSUS GAIN:
$4.67 PER HUNDREDTH
MARCH PERFORMANCE SERIES UNDERDRIVE PULLEYS
A 2-piece steel underdrive pulley set is inexpensive and will give a noticeable power increase as soon as you pull out of your driveway. By reducing the energy used to drive the engine accessories, underdrive pulleys free up horses and also increase accessory life (since the accessories don't have to spin as fast). A correctly designed set of pulleys will prevent overheating while idling and allow sufficient alternator speed to keep the battery charged; if the alternator doesn't stay charged, just install the crank pulley and leave the alternator pulley alone. Part No. 4005 is for 1988-92 cars.
THE CATCH:
None (but keep an eye on charging system voltage)
EASE OF INSTALL:
Moderate
WEAR AND TEAR:
Mild
APPROX. HP GAIN/ET REDUCTION:
10 HP
COST:
$52.50
COST VERSUS GAIN:
$5.25 PER HP
SLP THROTTLE BODY FLOW BOOSTER
SLP's throttle body Flow Booster (or "airfoil," as it is commonly known), Part No. 22100, increases flow through the L98's throttle body by decreasing turbulence that exists when air smacks the convoluted center section between the throttle body bores. It's never been clear why GM used a twin-bore throttle body instead of a single blade unit on this engine (space savings under the Corvette hood, most likely), but hey, we've got to deal.
THE CATCH:
None
EASE OF INSTALL:
Easy
WEAR AND TEAR:
Mild
APPROX. HP GAIN/ET REDUCTION:
4 HPCOST:
$34.95
COST VERSUS GAIN:
$8.74 PER HP
HOLLEY STEALTH RAM INTAKE MANIFOLD
The stock Tuned Port Injection system sitting atop L98s makes great low-end torque but takes the engine's breath away above 5000-rpm. Slap on a Holley manifold (Part No. 7540, unpolished) and let your motor breathe to 6000-revs or more. A fuel rail kit (Part No. 534-185) is also needed as the stock rails won't fit.
THE CATCH:
No EGR provision; stronger valve springs likely needed to prevent valve float at higher rpms
EASE OF INSTALL: Difficult
WEAR AND TEAR:
Mild
APPROX. HP GAIN/ET REDUCTION:
30 HP
COST:
$385.00
COST VERSUS GAIN:
$12.83 PER HP
ACCEL HEI CONTROL MODULE
The L98's ignition system needs to be upgraded if you're ever going to make any power. ACCEL's HEI control module pops under the distributor cap and gives an improved signal to the ignition coil for proper coil charging, thereby keeping the spark alive. The one pictured is Part No. 35362, for remote coil vehicles.
THE CATCH:
None
EASE OF INSTALL:
Easy
WEAR AND TEAR:
Minimal
APPROX. HP GAIN/ET REDUCTION:
3 HP
COST:
$43.88
COST VERSUS GAIN:
$14.63 PER HP
SLP COLD AIR INDUCTION PACKAGE
The Camaro's over-the-radiator air intake system and the Firebird's more traditional fenderwell intake system were pretty good at getting cold air into the L98 engine, but were unfortunately restrictive, thanks primarily to water and sound baffling. With a more direct airflow path and a cotton-gauze filter, SLP's system will wake up your F-body. The system shown, Part No. 21006, is for 1988 and 1989 cars; see SLP's Web site for other model years.
THE CATCH:
None
EASE OF INSTALL:
EasyWEAR AND TEAR:
Mild
APPROX. HP GAIN/ET REDUCTION:
15 HPCOST:
$249.95
COST VERSUS GAIN:
$16.66 PER HP
HOOKER SUPER COMPETITION HEADERS
While "shorty"-style headers give excellent gains on an L98, nothing beats a set of full-lengths. True, long tube headers are generally designed for high-rpm performance, which the stock TPI intake system is definitely not. But hopefully you'll be replacing that mess of silver snakes atop the engine anyway, so why buy headers twice? Be sure to get a good ceramic coating put on these puppies to prevent premature corrosion, and also to protect underhood parts from heat.
THE CATCH:
A Y-pipe will be needed to attach to the exhaust system; decreased ground clearance; computer recalibration likely necessary
EASE OF INSTALL:Difficult
WEAR AND TEAR:
Moderate
APPROX. HP GAIN/ET REDUCTION:
20 HP
COST:
$410.00
COST VERSUS GAIN:
$20.50 PER HP
CRANE CAMS GOLD RACE 1.6 RATIO EXTRUDED ROLLER ROCKER ARMS
Upgrading from stock 1.5 ratio rocker arms to a full-roller 1.6 ratio set yields increased valve lift as well as reduced valvetrain friction. As the vast majority of the added power comes from the extra valve lift, a simple swap to a 1.5 ratio roller rocker set will be a major waste of time and money. Cars with centerbolt valve covers need "narrow body" rockers, and Crane's Part No. 10758-16 is one of the few out there.
THE CATCH:
Minimal fuel economy decrease; reduced valvespring life
EASE OF INSTALL:
Difficult
WEAR AND TEAR:
Moderate
APPROX. HP GAIN/ET REDUCTION:
15 HP
COST:
$319.95
COST VERSUS GAIN:
$21.33 PER HP
MSD 6AL IGNITION CONTROL
Yet another upgrade to the L98's weak ignition system. A multi-spark, capacitive discharge ignition system like Part No. 6420 from MSD is an excellent power-building part that will complement any further engine modifications well. This model also has an adjustable "Soft Touch Rev Control" rev limiter to keep your L98 motor safe. Expect gains in gas mileage, throttle response, and engine smoothness too. Installation is easy with one of MSD's plug-and-play wiring harnesses (harness varies depending on coil style).
THE CATCH:
Spark plugs will need to be replaced more often
EASE OF INSTALL:
Moderate
WEAR AND TEAR:
Moderate
APPROX. HP GAIN/ET REDUCTION:
10 HP
COST:
$229.70
COST VERSUS GAIN:
$22.97 PER HP
MUFFLEX CAT-BACK EXHAUST SYSTEM
Whether a dual-cat or single-cat configuration, the exhaust on any L98 motor is restrictive at best. A 3.5-inch cat-back exhaust from Mufflex will free-up power and fuel efficiency and also outflow 3-inch systems. Mufflex offers its systems with Flowmaster or Spintech mufflers; choose the sound that's right for you. Check the Web site for complete offerings and part numbers.
THE CATCH:
Noise (not necessarily bad)
EASE OF INSTALL:
Moderate
WEAR AND TEAR:
Mild
APPROX. HP GAIN/ET REDUCTION:
18 HP
COST:
$490.87
COST VERSUS GAIN:
$27.27 PER HP