Get Up To “15” Extra Horsepower In 30 Minutes!
You’ll also get better fuel milage and increased accessory life!

What do Underdrive Pulleys do? Underdrive pulley systems increase engine horsepower by reducing the amount of power required to drive external engine accessories. For example, the alternator, power steering, water pump and air compressor rob horsepower from the engine. By replacing factory-sized crank and accessory drive pulleys with a resized pulley, the accessories are slowed, resulting in more horsepower available to the drive wheels. Typically, a set of Auto Specialties street pulleys will increase horsepower by 12-15, and increase mileage by 2 to 3 MPG. All pulleys are manufactured from Billet Steel or Aluminum, exceeding factory quality.

1998-02 LS1 25% Harmonic Dampner Crank, 15% Alt. Pulley Kit

ASP LS1 underdrive pulley kit reduces parasitic power losses associated with high accessory speeds, freeing up additional HP. It also reduces the rotating inertia on the front of the crankshaft allowing for faster revving. We have seen just over 13 rear wheel hp increase with this kit installed on stock LS1s.

NEW 2010 Camaro Pulley Kit (p/n# 541430)

Camaro / Firebird / Cadillac

Camaro / Firebird Street Pulleys
Black Nitride (Serpentine) .20
+ Second Quarter-Mile Gain
Part # ASP540801

Nitride Overdrive Alternator Pulley

“LT-1” 2 pulley Kit
“LT-1” 34% Add-On Crank Pulley 15% Alternator, .1 to .15 Second Quarter-Mile Gain
Part # ASP847601

Year Engine Pulley Description Full Charge Info Image Nitride Hard Coat Black Alum
2010-14 LS3/L99 15% Harmonic Dampner Crank 800 RPM ASP541430
$235.00
— N/A —
98-02 LS1 350 25% Harmonic Dampner Crank 800 RPM ASP948500
$265.00
— N/A —
98-02 LS1 350 25% Harmonic Dampner Crank
15% Alternator
950 RPM ASP948584
$275.00
— N/A —
93-97 LT1 350 34% Crank 950 RPM — N/A — ASP847600
$89.95
93-97 LT1 350 34% Crank
15% Alternator
1050 RPM — N/A — ASP847601
$109.95
93-97 LT1 350 23% Crank 800 RPM ASP945100
$165.00
— N/A —
93-97 LT1 350 23% Crank
15% Alternator
900 RPM ASP945103
$185.00
— N/A —
82-95  305, 350 25% Crank 800 RPM ASP540800
$94.00
— N/A —
88-92  305, 350 25% Crank
23% Alternator
950 RPM ASP540801
$101.95
— N/A —
88-95 2.8, 3.1, 3.4 25% Crank 900 RPM ASP541800
$74.95
— N/A —
88-95 2.8, 3.1, 3.4 25% Crank
23% Alternator
1100 RPM ASP541801
$94.95
— N/A —
85-87 305, 350 25% Crank 750 RPM ASP541100
$82.95
85-87 305, 350 25% Crank
23% Alternator
1000 RPM ASP541101
$102.95
82-85 305, 350
(3V-Groove)
25% Crank 750 RPM ASP541300
$88.95
ASP841300
$125.00
82-85 305, 350
(3V-Groove)
25% Crank
12% Alternator
950 RPM ASP541302
$109.95
ASP841302
$145.00

Cavalier

Year Engine Pulley Description Full Charge Info Image Clear Coat Alum
96-00 2.4L Cavalier 25% Crank — N/A — ASP840096
$124.95

Corvette / Cadillac CTS-V

Year Engine Pulley Description Full Charge Info Image Nitride Hard Coat Black Alum
04 350 LS1 Cadillac CTSV NA 900 RPM ASP941020
$248.00
— N/A —
97-09 350 LS1/ LS2 / LS3 25% Harmonic Dampner Crank
10% A/C Reduction
850 RPM ASP941020**
$248.95
— N/A —
93-96 350 LT1 22% Crank 800 RPM ASP945800*
$165.00
— N/A —
93-96 350 LT1 22% Crank
15% Alternator
900 RPM ASP945803*
$185.00
— N/A —
84-91 350  22% Crank 750 RPM ASP540200
$82.95
— N/A —
84-91 350 22% Crank
23% Alternator
950 RPM ASP540201
$105.00
— N/A —
88-91 350 22% Crank
23% Water Pump
750 RPM ASP540220
$125.95
— N/A —
88-91 350 22% Crank
23% Alternator
23% Water Pump
950 RPM ASP540221
$155.95
— N/A —
75-82 350 28% Crank 800 RPM ASP542100
$125.00
ASP842100
$125.95
75-82 350 28% Crank
12% Alternator
1000 RPM ASP542102
$145.00
ASP842102
$145.95
71-74 350 25% Crank 800 RPM ASP543400
$224.00
ASP843400
$125.95
71-74 350 25% Crank
12% Alternator
900 RPM ASP543402
$145.00
ASP843402
$145.95

* Will not work with LT-4
** Will not work on Z06

Pontiac

Year Engine Pulley Description Full Charge Info Image Nitride Hard Coat Black Alum
09-11 LS2 — N/A — ASP540025
$248.00
— N/A —
98-04 GTP Eaton 90SuperCharged 3.25″ +6 lbs of Boost, Requires #003435 — N/A — ASP540032
$99.95
— N/A —
98-04 GTP Eaton 90SuperCharged 3.40″ +4 lbs of Boost, Requires #003435 — N/A — ASP540034
$99.95
— N/A —
98-04 GTP Eaton 90SuperCharged 3.50″ +2 lbs of Boost, Requires #003435 — N/A — ASP540035
$99.95
— N/A —
98-04  Pontiac GTP Pulley Puller Required for 540034 & 540035 ASP003435GT
$130.00
91-96 3.4L Pontiac Grand Prix 20% Crank — N/A — — N/A — ASP840104
$124.95
91-96 3.4L Z – 34 * 20% Crank — N/A — — N/A — ASP840104
$124.95
96-00 2.4L Pontiac Sunfir