When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Works as a 1 or 3 wire operation, Black finish with fan baffle for added heat dissipation, Includes a single groove pulley that will accept a V-style belt, Puts out 150 amp with 90 amps at idle, and 125 amps at cruising speed, Designed to fit GM models from 1965-'85 with straight mount 6.61 inch bolt spacing Powermaster 47294 GM 12SI 150 Amp Alternator, Natural Sku # 25547294 Mfr. Part # 47294 Condition New Brand Powermaster Sold Each Details
Powermaster's most popular GM alternator fits most models, 1965-'85 with straight mount 6.61 inch bolt spacing.
- Works as 1 or 3 wire operation
- Internally regulated
- Pulley included, single groove
- V-belt style
- 150 amp with 90 amps at idle, and 125 amps at cruising speed
- Black finish with fan baffle
Alternator FAQ (Link)
See the difference between the popluar alternators we offer by reading our tech article, GM Alternator Buying Guide (Link) and learn how to correctly install your new 1-wire alternator by reading our tech article, 1-Wire Alternator Conversion (Link).
Specs One Wire Alternator Yes Alternator Case Style GM 10SI/10DN/12SI Alternator Amperage 150 amp Voltage Required 12-Volt Regulator Internal Regulator Style Internal Alternator Finish Natural Regulator Included Yes Alternator Pulley Included Yes Belt Width 0.375" Alternator Brackets Included No Overall Length 6.25" Color Natural Sold in Quantity Each Centerline of Holes 6.61" MFG. Part # 47294 Notes Made in the USA GTIN Code 692209002475 Belt Included No Pulley Style V-belt Belt Type V-Belt Reviews Yes would buy again Rated by Dan on June 26, 2026
Summary: Keeps up with electric demands on my street rod
Yes, I recommend this product.
Great product Rated by Chris on December 07, 2025
Summary: I run this on my '57 Chevy and it makes plenty of amperage to run AC, electric fan, radio, and all of the accessories.
Yes, I recommend this product.
Nice clean assemble of a GOOD product!! Rated by Buckchop on April 05, 2025
Summary: 69 bbc camaro
Yes, I recommend this product.
I would buy again Rated by Eric on February 24, 2024
Summary: Work great and looks perfect ran the air ride/subs and lights all at the same time never dim down works great
Yes, I recommend this product.
I would buy it again Rated by Eric on February 14, 2024
Summary: Works great
Yes, I recommend this product.
Related Items / Suggested Parts GM 12SI 150 Amp Plain Alternator and SBC Upper Bracket GM 12SI 150 Plain Alternator with SBC Alternator Bracket, Plain Tuff Stuff 754636 36 Inch 8 Gauge Charge Wire With Boot Speedway GM Internally-Regulated Alternator Wiring Harness Tech Support We're here to help before and after your purchase. If you have a question or need assistance with one of our products, please contact us through Messaging and a knowledgeable Speedway Motors team member will be happy to help. About Speedway Motors is America’s Oldest Speed Shop® and has been a trusted source for specialty rodding and racing products and friendly expert advice for more than 74 years. Founded in 1952 by “Speedy” Bill Smith – a racer and street rodder himself – Speedway has grown from a one-man operation to become the world’s largest manufacturer, distributor and retailer of street rod and racing products. Our industry-leading fast delivery is the result of same-day shipping from our state-of-the-art, centrally located 500,000 sq. ft. headquarters. Speedway’s size offers customers unmatched product selection and low pricing, while our excellent technical support and customer service have made us a recognized leader in the rodding and racing industries.
