12SI Motor Swap High Output Alternator - One Wire Turn On by JS Alternators

SKU: 8302-320-467

$647.17 CAD $820.13 CAD

Shipping calculated at checkout.

Amperage 320 amps 6 phase hairpin 250 amps 6 phase hairpin

Pulley V-Belt Double V-Belt 6-Rib Serpentine Pulley

FIP Ships JS Alternators To Canada Starting July 1, 2026

Copy the SKU# (include AMPS selection) then click the link below. Give us your shipping address, PASTE THE SKU and we will email you a SHIPPED QUOTE. If you need expited shipping, include that info as well.

Hairpin units are commonly called 6 phase. They produce more output at idle and are more efficient than a conventional alternator. JS Alternators hairpin units feature premium bearings to withstand high engine rpm and utilize dual plate rectifier with 12 heavy duty diodes for improved cooling. Hairpin Units are a more reliable alternator to withstand high heat, high demand for car audio, marine, and racing applications.

This unit is a direct replacement for standard Delco 10DN, 10SI, and 12SI alternators, making it easy to install on most 1963-1985 GM vehicles. To activate the alternator, you only need to connect a single wire from the provided pigtail to any ignition switched 12V+ source. This allows the alternator to turn on and off with the ignition switch. These units come with a smaller pulley which requires installing a half inch to an inch shorter belt. Make sure to select the pulley design needed for your vehicle in the drop down menu.

All Motor Swap Applications will come with a 45 mm. pulley and will require installing a 1/2 inch - 1 inch shorter belt.

FITMENT GUIDE:

Make	Model	Engine	Year(s)
BUICK	All Early Models	Most Engines	63-79
BUICK	Gran Sport	All Engines	65-67
BUICK	Riviera	All Engines	63-70
BUICK	Skylark	All Engines	63-79
BUICK	Wildcat	All Engines	63-70
CADILLAC	All Early Models	All Engines	63-85
CHEVROLET	All Early Models	Most Engines	63-85
CHEVROLET	C10 Pickup	All Engines	63-78
CHEVROLET	Camaro	All Engines	67-80
CHEVROLET	Caprice	All Engines	66-77
CHEVROLET	Chevelle	All Engines	64-73
CHEVROLET	Chevy II	All Engines	63-68
CHEVROLET	Corvette	All Engines	63-79
CHEVROLET	El Camino	All Engines	64-77
CHEVROLET	Impala	All Engines	63-77
CHEVROLET	Malibu	All Engines	64-77
CHEVROLET	Monte Carlo	All Engines	70-77
GMC	All Early Models	All Engines	63-85
GMC	C15 Pickup	All Engines	67-78
OLDSMOBILE	All Early Models	V-8	63-85
OLDSMOBILE	442	All Engines	65-71
OLDSMOBILE	Cutlass	All Engines	63-76
OLDSMOBILE	F85	All Engines	63-72
PONTIAC	Early models	V-8	63-85
PONTIAC	Firebird	All Engines	67-70
PONTIAC	GTO	All Engines	64-71
PONTIAC	Tempest	All Engines	63-70
PONTIAC	Ventura	All Engines	71-77

JS Alternators frequently asked questions

Orders ship in approximately 5-15 business days, sometimes sooner. Alternators that require a custom bracket can take 10-25 business days.If for some reason parts are on back order, we will notify you, but this is not common. If payments are being made on an order, your order will start processing when the order is placed.

We offer lifetime warranty on alternator labor and a one year warranty on parts. All orders are heavily wrapped for shipping with several layers of big bubble wrap and two layers of boxes along with a Fragile sticker on the box. If you have to ship your alternator back, please be sure you wrap it the same way to prevent further damage.

Yes. Please fill out our return form at https://js-alternators.com/pages/rga-request-returnsIf this is filled out prior to your one-year date, we will honor the warranty for an additional 90 days.

Each of our high output alternators come with smaller overdrive pulley. This pulley is made to increase low RPM charging for maximum output. It is custom for the diameter of the overdrive to be less than your factor pulley, depending on the kind of vehicle you own. For this reason, unless otherwise specified, you will need at least a 1/2 inch shorter belt. You can purchase this from any auto parts store. In using the belt and the pulley system, ensure that each part of the pulley system is free of oil or grease, this will help its efficiency.

It is important to make sure that the small regulator plug that is located on the back of the alternator is well plugged in for the correct functionality. Do not forget to plug it in completely, try not to jam the plugs in backwards, and avoid pinching it in order not to create a short. For more information on regulators and wiring see installation instructions.

Our high output alternators come with an overdrive pulley. The pulley is designed to improve low RPM charging so that it yields maximally. Do not change this overdrive pulley out with a larger diameter pulley. When alternator pulley diameter is increased, the output amperage decreases. Changing the pulley will void all warranties

As promised to all our customers, our products are fully tested ensuring their outstanding performance before shipping. In our experience through the years, it is in many cases not the alternator itself. You must ensure you consider a few possible concerns in your troubleshooting – please read the instruction manual thoroughly.

The reason could be one of two things: Either the plug is wired incorrectly or the computer is sensing the higher voltage and causing the battery light to come on even though the alternator is charging properly. Please refer to the instruction manual tab on the website for specific instructions that will help you with wiring. For some older vehicles, the factory style regulator is not available with the hairpin style alternator. This is why your high output alternator will come already “upgraded” with the 15 volt regulator. It will have an oval plug which requires splicing into the factory plug. This is a simple ,fast step and these instructions are detailed for you in the instruction manual.