High Performance Pulleys

From the factory your 1978 GMC C15 is equipped with multiple pulleys. Pulleys are responsible for guiding and tensioning belts throughout the engine. The belts are connected to various engine accessories such as your water pump, your AC compressor, alternator, and power steering pump. High Performance Engine Pulleys are made from a lightweight material. Most pulleys are a direct replacement for your OE pulleys. Performance pulleys also add a nice clean polished look to your engine bay, no matter the finish you decide to go with. Sport Compact Warehouse is your premier source for performance engine pulleys. Reach out to one of our experienced representatives if you have any questions and we will help you make a more informative decision.

In the accessory drive system, the crankshaft drives the water pump, alternator, power steering pump, A/C compressor and other accessories via an arrangement of pulleys mounted to each component and one or more drive belts. While the amount varies according to vehicle, all accessories use up horsepower – power that could be applied to your drive wheels. But there are ways to reduce your accessories’ power consumption without negatively affecting function.

You can gain horsepower by reducing the weight of your pulleys and by changing their diameter. We offer aluminum pulleys that are much lighter than the original equipment pulleys, without any reduction in strength. These pulleys are direct replacements and require no modifications for installation. Their light weight not only results in a horsepower increase, but the reduced rotational mass also improves throttle response.

Reducing the diameter of the crankshaft drive pulley or increasing the diameter of the driven accessory pulley underdrives the accessory, slowing its rotational speed and reducing the amount of horsepower it draws. However, the size of the pulleys must be carefully calculated so your accessories continue to operate properly. Everyone wants more horsepower, but not with adverse side effects like reduced power steering assist, an alternator that doesn’t charge the battery, or an overheated engine. Our pulley kits have been extensively tested to deliver maximum horsepower with no loss of accessory functionality.

Using underdrive pulleys to reduce accessory drag is an easy and inexpensive way to gain as much as 15 horsepower! Each kit is engineered for the specific application, ensuring straightforward installation. Most kits are designed to use the existing serpentine belt, but a belt is supplied if a different length is required. Most lightweight and underdrive pulleys are machined from high grade aluminum alloy, some with an attractive chrome or anodized finish, so if not for the horsepower increase, you’ll want them just for an engine appearance upgrade.

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AEROMOTIVE 21106
Please Note:

Some images might not represent the actual product

AEROMOTIVE 21106 Billet Pulley Drive Mandrel Type II
for 1978 GMC C15 BASE

$249.49

Save: $32.54
Sale Price:

$216.95

Estimated Ship Date: Today

Free DelieveryFree Ground Shipping
In Stock - 2 New In Stock
EngineFit NotesFitment Notes
1978 GMC C15 BASE equipped with
7.4L V8 Gas OHV
 
Cab & Chassis 2-Door
 
1978 GMC C15 BASE equipped with
7.4L V8 Gas OHV Cab & Chassis 2-Door
,
MR GASKET 5318
Please Note:

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MR GASKET 5318 Crankshaft Pulley Triple Groove Long Water Pump
for 1978 GMC C15 BASE

$130.23

Save: $16.99
Sale Price:

$113.24

Estimated Ship Date: Today

In Stock - 1 New In Stock
EngineFit NotesFitment Notes
1978 GMC C15 BASE equipped with
6.6L V8,
5.7L V8,
5.0L V8
 
Engine Crankshaft Pulley
Triple Groove
Long Water Pump
 
1978 GMC C15 BASE equipped with
6.6L V8,
5.7L V8,
5.0L V8 Engine Crankshaft Pulley
Triple Groove
Long Water Pump
,
MR GASKET 4977
Please Note:

Some images might not represent the actual product

MR GASKET 4977 Crankshaft Pulley Double Groove Long Water Pump
for 1978 GMC C15 BASE

$89.39

Save: $11.66
Sale Price:

$77.73

Estimated Ship Date: Today

In Stock - 3 New In Stock
EngineFit NotesFitment Notes
1978 GMC C15 BASE equipped with
6.6L V8,
5.7L V8,
5.0L V8
 
Engine Crankshaft Pulley
Double Groove
Long Water Pump
 
1978 GMC C15 BASE equipped with
6.6L V8,
5.7L V8,
5.0L V8 Engine Crankshaft Pulley
Double Groove
Long Water Pump
,
MR GASKET 4961G
Please Note:

Some images might not represent the actual product

MR GASKET 4961G Crankshaft Pulley Triple Groove Long Water Pump
for 1978 GMC C15 BASE

$87.33

Save: $11.39
Sale Price:

$75.94

Estimated Ship Date: Today

In Stock - 14 New In Stock
EngineFit NotesFitment Notes
1978 GMC C15 BASE equipped with
7.4L V8
 
Engine Crankshaft Pulley
Triple Groove
6 3/4 in. Dia. Inner Groove
7 7/8 in. Dia. Outer Groove
Long Water Pump
 
1978 GMC C15 BASE equipped with
7.4L V8 Engine Crankshaft Pulley
Triple Groove
6 3/4 in. Dia. Inner Groove
7 7/8 in. Dia. Outer Groove
Long Water Pump
,
MR GASKET 4976
Please Note:

Some images might not represent the actual product

MR GASKET 4976 Crankshaft Pulley Single Groove Long Water Pump
for 1978 GMC C15 BASE

$67.59

Save: $8.82
Sale Price:

$58.77

Estimated Ship Date: Today

In Stock - 1 New In Stock
EngineFit NotesFitment Notes
1978 GMC C15 BASE equipped with
6.6L V8,
5.7L V8,
5.0L V8
 
Engine Crankshaft Pulley
Single Groove
Long Water Pump
 
1978 GMC C15 BASE equipped with
6.6L V8,
5.7L V8,
5.0L V8 Engine Crankshaft Pulley
Single Groove
Long Water Pump