{
    "lazyNodes": false,
    "abFitnotesFlag": false,
    "abCrawlReviews": true,
    "productOptionsCookie": false,
    "orderDelayFlag": false,
    "skipSessionCookie": false,
    "covidMessage": false,
    "fullTitleCookie": false,
    "nrLoggerCookie": true,
    "checkoutReviewCookie": false,
    "productOptionSeqCookie": false,
    "maintenanceFlag": false,
    "bufferETACookie": false,
    "multiShippingDiscountFlag": false,
    "newFitmentFlag": false,
    "surveyOptInFlag": true,
    "crossSellFlag": false,
    "skuMappingFlag": false,
    "paySplitCookie": false,
    "callDisableFlag": true,
    "zipPaymentFlag": "c",
    "hassleFreeReturn": true,
    "lifetimeReplacement": true,
    "cpn_off": false
}
Select your vehicle
Vehicle Info Required to Guarantee FitAdd Vehicle

AC Delco®
SET-AC21-8 RapidFire Performance Platinum Series Spark Plug, Set of 8

Tap image and pinch to zoom.
$44.49
OR
Manufacturer #SET-AC21-8
Vehicle Info Required to Guarantee FitAdd Vehicle
Qty:
1

Included in This Kit

Qty
Part
Brand
Location
Replaces OE Number
Spark Plug
AC Delco
-
-

Highlights

Brand:
Series:
RapidFire Performance Platinum Series
Electrode Tip Material:
Platinum Electrode Tip
Quantity Sold:
Set of 8
Warranty:
24-months or unlimited mile AC Delco limited warranty
Prop 65 Warning:

Warning SymbolWARNING: This product can expose you to chemical which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

Gap Size:
0.05 in.
Heat Range:
8
Reach:
1.04 in. Reach
Thread Size:
14 mm thread size

Vehicle Fitment Information

Vehicle Name
Submodel
Engine
Fitment Information
2003 Mercedes Benz S55 AMG
Kompressor
8 Cyl 5.5L
2 Plugs/Cylinder; Gap .032
2003 Mercedes Benz SL55 AMG
Kompressor
8 Cyl 5.5L
2 Plugs/Cylinder; Gap .039
2003-2004 Infiniti M45
Base
8 Cyl 4.5L
Gap .044
2003-2006 Mercedes Benz CL55 AMG
Base
8 Cyl 5.5L
Gap .040
2003-2006 Mercedes Benz E55 AMG
Base
8 Cyl 5.5L
2 Plugs/Cylinder; Gap .039
Page 1 of 17 | Showing 1 - 5 of 81 results

Product Information

ACDELCO RAPIDFIRE PERFORMANCE PLATINUM SPARK PLUG

Fire up your engine with the rapid response and enduring, streamlined performance of ACDelco’s RapidFire Performance Platinum spark plug. Established in 1899, ACDelco manufactures original GM parts and premium OE replacement parts for other brands in the automotive aftermarket.

  • Tapered center wire electrode minimizes firing diameter for improved efficiency
  • Insulator’s ribless design provides secure seal
  • Required voltage for firing has been dramatically reduced
  • Solid state suppressor protects against compression leakage and radio interference
  • Engineered for enduring, streamlined performance
  • Wards off rust and wear over time
Need help?Call our product expert1-866-529-0412
Chat with us
Mondays - Sundays7am - 11pm ET | 4am - 8pm PT
Warranty Policy
Right parts, guaranteed. If you find any defects, let us know within 60 days and we’ll take care of it. Check out our Warranty Policy for more details.
Shipping Policy
We ship fast so you can get on the road that much faster. Check out our Shipping Policy for more details.
Easy Return Policy
We’re only happy if you’re happy. If you’re not entirely satisfied with your order, you may be entitled to a refund. Check out our Return Policy for more details.

Product Q&A

0
Are they galled to .40 already?Rosa R.Aug 01, 2023
Best Answer:Hi Rosa, thank you for reaching out. The pre-gap size of this item is 0.045 inches (1.100 millimeters), if that is what you mean. If your vehicle information matches this product, you can use this link to order the part and take advantage of our low price for this item: <a href="https://www.carparts.com/spark-plug/ac-delco/set-ac21-8?can=CPAP3648_CSQA_20230801" target="_blank">https://www.carparts.com/spark-plug/ac-delco/set-ac21-8?can=CPAP3648_CSQA_20230801</a> I hope this helps. Enjoy shopping.
Aldrin P.STAFFAug 01, 2023

Customer Reviews

great product!
CHARLES B.
VERIFIED PURCHASER
Purchased on Jul 12, 2023