400 (3L80), AT-540, Powerglide, Powerglide, 350, 400 (265mm) Performance Converter

265mm Performance Converter Kit
Part No. GM-RK-355

View Instructions

Sonnax 265mm performance converter kit GM-RK-355 for 35-spline GM Powerglide and TH400 265mm applications allows builders to assemble a high performance converter with minimal effort. Powerglide transmissions must be upgraded with the 35-spline Sonnax big input shaft kit 353532-01K. With the readily available GM 265mm converter cores, a variety of stall speeds can be built using different stator and impeller combinations.

  • Fully machined cover with bushing installed
  • Unit-specific design for hassle-free installation
  • Oil flow grooves and holes increase fluid flow to keep converters running cooler
  • Turbine hub features a larger flanged diameter to increase the strength rigidity of the turbine
  • Clear, detailed instructions

Pilot kit not included.

This 265mm kit will not fit GM AT-540 units. View Sonnax 245mm converter upgrades available for this unit.

  • Thrust Bearing
  • Flanged Impeller Hub
  • 35-Tooth Turbine Hub
  • Front Cover, 10-3/4" Single Bolt Pattern
  • Front Cover Bushing Installed
  • Unit Size: 265mm
  • Core: 265mm
  • Dampered: No
  • Lockup: No
  • Transmission Unit: TH400, Powerglide
  • Turbine Hub Input Spline Count: 35

Where to Buy

  • Existing Customers: Contact your sales representative.
  • New Customers: Fill out the form and a sales representative will contact you.
  • 400 (3L80), AT-540, Powerglide, Powerglide, 350, 400 (265mm) Performance Converter 265mm Performance Converter Kit  GM-RK-355

Sonnax Performance Converter Kits

Engineered to Deliver Builds that Last

Designed from the ground up to outperform OE and other aftermarket components, Sonnax has you covered with a full line of performance converter kits for gas and diesel vehicles. Offering the widest variety of options in the aftermarket, these innovative kits deliver customized performance and value.

  • Small/Large Diameter
  • Single-Plate/Multi-Plate/Non-Lockup
  • Dampered/Damperless


Choose the right kit for your rebuild!