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Description
The Powermaster GM 12si 100 Amp Alternator is a versatile, high-performance upgrade designed for classic muscle cars, hot rods, and trucks. Based on the iconic "large case" 12si design, this unit provides a significant power boost over original 37-amp or 63-amp factory alternators, making it ideal for vehicles with upgraded ignition systems, electric fans, or high-output audio.
Performance & Output
The 12si series is favored for its superior cooling and higher output at lower engine speeds compared to the older 10si models:
Peak Power: Delivers 100+ Amps at top-end RPMs to handle full electrical loads.
Idle Performance: Engineered to provide a robust 75+ Amps at idle, ensuring your battery stays charged even while sitting in traffic with the lights and fans running.
Thermal Efficiency: The 12si housing features an improved fan and internal design for better heat dissipation, extending the life of the internal components.
Versatile "1 or 3 Wire" Installation
This alternator offers the ultimate flexibility in wiring, making it compatible with almost any classic GM-style electrical system:
1-Wire Operation: Simplifies your engine bay by requiring only a single heavy-gauge cable running from the alternator to the battery. It "self-excites" once the engine reaches a specific RPM.
3-Wire Operation: Allows you to retain your factory dashboard "Gen" or "Alt" warning light and utilize the factory remote-sensing wire for more accurate voltage regulation at the main junction block.
Internal Regulator: Features a built-in internal regulator to ensure steady voltage without the need for an external "voltage regulator" box on the firewall.
Quality and Reliability
Classic Look: Retains the traditional GM aesthetic, fitting perfectly into stock brackets and maintaining an authentic appearance in your engine bay.
Individually Dyno Tested: Every Powermaster unit is tested on a dynamometer before shipping. You receive a Proof of Performance guarantee (actual test results) inside the box.
Solid Pulley: Comes equipped with a standard solid V-belt or serpentine pulley (depending on the specific part number) for a secure, non-slip drive.
Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.
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Refund Policy
We offer a 30-day return policy, which means you have 30 days from the date you receive your item to request a return.
Eligibility for Returns
To be eligible for a return, your item must be:
In the same condition as received
Unworn or unused
With original tags attached
In its original packaging
You must also provide a receipt or proof of purchase.
How to Start a Return
To initiate a return, please contact us at jonathon@hotrodhardware.com. Once your return request is approved, you will be provided with the return address and, if applicable, an RMA (Return Merchandise Authorization) number.
Important: Items sent back without prior authorization will not be accepted.
If you have any questions regarding your return, feel free to contact us at the email above.
Damages and Issues
Please inspect your order upon delivery. If your item is defective, damaged, or if you received the wrong item, contact us immediately so we can evaluate the issue and resolve it promptly.
Exceptions / Non-Returnable Items
The following items are not eligible for return:
Custom or personalized products (including special orders)
Hazardous materials, flammable liquids, or gases
Sale items
Gift cards
If you are unsure whether your item qualifies, please contact us before initiating a return.
Exchanges
The fastest way to receive a replacement item is to return your original item (once approved) and place a new order separately.
Free Shipping Orders
Orders that qualified for free shipping are subject to deduction of the original outbound shipping cost if the item is returned.
Refunds
Once your return is received and inspected, we will notify you regarding the approval status of your refund.
If approved:
Refunds will be issued to your original payment method
Any applicable restocking fees will be deducted
Original shipping charges (if applicable) will be deducted
Return shipping costs (if arranged by Hot Rod Hardware) will be deducted
Please note:
Payment processing fees (including PayPal, Amazon Pay, or other merchant fees) are non-refundable
It may take additional time for your bank or credit card provider to process and post the refund
