The ATI 915663 SFI Flexplate is a performance-focused replacement flexplate engineered for select early Gen 3 HEMI vehicles using internally balanced 5.7L and 6.1L engines. Built from SFI-spec steel and certified to SFI 29.1 standards, this flexplate provides the strength and precision needed for performance street cars, drag racing combinations, and upgraded automatic transmission setups. ATI manufactures its flexplates using OEM drawings to maintain accurate fit and positioning while applying tighter quality controls for flatness, runout, and balance. The 915663 features a 131-tooth ring gear and neutral balance configuration for compatible internally balanced engines. For HEMI owners increasing power, upgrading the torque converter, or refreshing the drivetrain, this ATI flexplate offers a purpose-built alternative to relying on an aging factory component.

A flexplate serves as the critical connection between the engine crankshaft and automatic transmission torque converter. In a performance Gen 3 HEMI, that connection can be subjected to significantly greater loads during hard launches, high-RPM shifts, and repeated drag strip passes. Increasing engine output and installing a higher-stall or performance torque converter can make the strength and condition of the flexplate even more important.

ATI constructs its performance flexplates from SFI-spec steel and uses double welding for additional strength and long-term precision. Each flexplate is manufactured and toleranced using OEM drawings, then inspected to exceed OEM flatness and runout tolerances. ATI also precision balances its flexplates using Hines digital balancing equipment with a stated resolution of 0.10 oz-in.

Unlike rigid plate designs that can eliminate the characteristics that give a flexplate its name, ATI’s Superplate is designed to retain the ability to flex similarly to an OEM-style plate. This allows the component to accommodate the small machining and alignment tolerances present throughout an engine and transmission assembly while still providing the additional construction quality expected from a performance drivetrain component.

ATI lists 915663 for 2005-2008 Chrysler 300C, Dodge Charger, and Dodge Magnum applications equipped with the 5.7L or 6.1L Gen 3 HEMI. ATI also lists 2005-2007 Jeep Grand Cherokee applications with the 6.1L HEMI, while specifically stating that this flexplate does not fit the 5.7L Jeep Grand Cherokee. The manufacturer further notes that OEM torque converter bolt holes require the longer bolts included with the application.

This makes the ATI 915663 a strong option for early HEMI performance builds, particularly SRT8 and modified R/T combinations that see increased drivetrain load. It can be incorporated into torque converter installations, transmission upgrades, engine swaps using the appropriate factory-style transmission configuration, or comprehensive drivetrain rebuilds. Because flexplate compatibility depends on crankshaft, transmission, converter, and vehicle configuration, exact fitment should always be confirmed before installation.

Whether you’re refreshing a street-driven 5.7L HEMI or preparing a 6.1L SRT8 for harder launches and more power, the ATI 915663 SFI Flexplate provides the strength, precision manufacturing, and certified construction expected from a serious Gen 3 HEMI drivetrain upgrade.

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Specifications & Features

• Manufacturer: ATI Performance Products
• Manufacturer Part Number: 915663
• Product Line: ATI SFI Approved Flexplates
• Product Type: Performance automatic transmission flexplate
• Material: Steel
• Engine Balance: Internal/neutral balance
• Safety Certification: SFI 29.1
• Ring Gear Tooth Count: 131 teeth
• Rear Main Seal Style: 1-piece
• Vehicle Compatibility: Select Chrysler 300C, Dodge Charger, Dodge Magnum, and Jeep Grand Cherokee applications
• Engine Compatibility: Select 5.7L and 6.1L Gen 3 HEMI engines
• Year Compatibility: 2005-2008 Chrysler 300C, Dodge Charger, and Dodge Magnum 5.7L/6.1L applications. 2005-2007 Jeep Grand Cherokee 6.1L applications.
• Jeep Fitment Note: Does not fit 5.7L Jeep Grand Cherokee applications.
• Torque Converter Hardware: ATI notes that OEM converter bolt holes require longer bolts, which are included for the listed application.
• Package Size: Approximately 14.50 x 14.30 x 1.20 inches according to current retail specifications
• Shipping Weight: Approximately 6.77 lbs.
• Color / Finish: Natural steel appearance; exact finish not specified by manufacturer
• Quantity: Sold individually
• Construction: SFI-spec steel with double-welded construction
• Manufacturing: Produced from OEM drawings for accurate fit and positioning
• Balance Quality: Precision balanced using Hines digital equipment with 0.10 oz-in resolution
• Recommended Uses: Performance street builds, drag racing, torque converter upgrades, transmission upgrades, drivetrain rebuilds, and higher-output Gen 3 HEMI combinations
• Primary Benefits: Increased performance-oriented construction, SFI certification, precise fitment, controlled flex characteristics, accurate balancing, and suitability for demanding HEMI drivetrain applications
• Fitment Note: Verify engine, crankshaft, transmission, torque converter, and vehicle configuration before ordering.

Note:
🚫 May not fit 5.7L Grand Cherokee
🚫 May not work on RAM with 8-speed
🚫 Not for V6 engines (they know what they did)
🚫 Does not fit RFE transmissions