Product Description

Michigan Motorsports LS1 Crankshaft Flexplate Adapter Spacer

Fits GM TH350, TH400 & 700R4 Conversions | Centers Torque Converter to Curved LS Flexplates

Ensure proper torque converter engagement when installing a TH350, TH400, or 700R4 behind an LS engine with this Michigan Motorsports LS1 Crankshaft Flexplate Adapter Spacer. Designed to correctly center the nose of the torque converter when using a stock curved LS flexplate, this spacer provides the alignment and spacing required for reliable drivetrain operation. Perfect for LS swap builds, transmission conversions, and retrofits seeking OEM-level fitment and durability.

Key Features

Correct Converter Alignment: Centers the torque converter snout to the curved LS flexplate for proper engagement and driveline reliability.
Essential for LS Swaps: Required when adapting TH350, TH400, or 700R4 transmissions to LS engines using factory curved flexplates.
Durable Construction: Precision-machined for a perfect slip-fit and long-term durability in performance or street applications.
Simplifies Conversions: Eliminates guesswork during LS retrofit installations, ensuring proper spacing without additional adapters.
Direct Fit: Works with all LS-based engines using TH350, TH400, or 700R4 transmissions.

Key Fitments

Engines: Compatible with all GM LS-based engines including 4.8L, 5.3L, 5.7L (LS1), 6.0L, 6.2L, and 7.0L (LS7).
Platforms: Designed for LS swap applications using TH350, TH400, or 700R4 transmissions with factory curved LS flexplates.
Notes: Required for proper torque converter snout centering. Not needed when using flat flexplates or LS-specific torque converters.

Product Videos

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How to: LS1 LSX 4.8 5.3 6.0 engine swap transmissions adapter. www.MichiganMotorsports.com

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Product Reviews

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5
Adaptor

Posted by Neil nykanen on Dec 8th 2025

Works as expected.
5
Perfect!

Posted by BJ Maynard on Sep 15th 2021

I have a TH350c Lock Out Transmission mounting on a 5.3 LS motor and this adapter worked perfect. Thank You!
5
Flexplate Adapter

Posted by David Nordman on Sep 25th 2020

Michigan Motorsports was wonderful to work with!
5
Swap

Posted by Ricardo Martir on May 20th 2020
5
I don't know if this part is going to work,but it was sent/delivered pronto

Posted by John on Apr 15th 2019

I'm impressed find it, buy it ,recieve it,install it and enjoy it
5
Great part

Posted by John Race on Aug 6th 2018

I bought the ls swap spacer for TH400, it works great . Thank you
5
Flexplate adapter

Posted by Jesus sauceda on Jun 23rd 2018

Awesome product fits perfect
5
crank spacer

Posted by ernest on May 28th 2018

great part don't need anything but this spacer and elongate flex plate converter holes the job is done
5
Ls1 flexplate adaptor

Posted by Josh on Mar 10th 2018

Great finish and fit. Worked like a dream.

LS1 Torque Converter Crankshaft Flexplate Adapter Spacer TH350 TH400 700R4 Conversion Swap LS2 LS3 LS6 5.3 6.0 LS7