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LS4 King

Solid LS4 Engine & 4T80E Trans Swap Mount Kit

Solid LS4 Engine & 4T80E Trans Swap Mount Kit

Regular price $549.99 USD
Regular price Sale price $549.99 USD
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Solid Engine & Transmission Mount Kit for the LS4 to 4T80E Conversion

The biggest pitfall of the W-Body platform has always been the transmission. Once the threshold of 450whp has been crossed, even the healthiest 4T65E quickly becomes a time bomb. Countless builders have attempted to reengineer the 4T65E using expensive exotic parts only to experience continued failures. Several years back, Brandon Furches of LS4 King paved the way for LS4 enthusiasts in the form of the 4T80E swap. Utilizing the robust transaxle found in front wheel drive Northstar powered vehicles has proven time and time again to be a viable option for builders looking to push the limits of the LS4.

This is a conversion which LS4 King has constantly refined over the years. After logging thousands of miles and countless hours of abuse, we are pleased to offer the most durable and well engineered mount kit to facilitate the 4T80E conversion.

Our three piece mount kit is intended to be a direct bolt-on to your aluminum LS4 subframe. Each mount has been precision machined or carefully tig welded within a fixture to guarantee a perfect fit. The solid design of this triangulated mount kit greatly reduces the movement of the powertrain package allowing the user to put more horsepower and torque to the pavement. This kit also allows users to eliminate the upper torque mount also known as the dog bone which in turn frees up additional real estate in the engine bay. Each kit comes complete with new metric 10.9 flange bolts as well as a billet aluminum bell housing clamp. 

A note from Brandon: One misconception I often hear repeated is that solid mounts equal teeth chattering ride quality. This is completely false. You will have a moderate increase in NVH (Noise Vibration Harshness) since the engine and transmission no longer ride on squishy rubber mounts, this is to be expected. It is extremely tolerable and in my opinion simply creates more feedback from the chassis to the driver. I daily drive my swapped vehicles and I have never received a complaint from any of my passengers.    

  • Please note:
  • This mount kit is intended for LS4 & 4T80E Swaps only. These mounts will NOT work in conjunction with the OEM 4T65E.
  • If you are attempting to swap a W-Body originally equipped with a V6, you will also need the LS4 subframe. These mounts will NOT work with the V6 subframe.
  • Due to the increased footprint of the 4T80E this mount kit moves the drivetrain forward towards the radiator support one inch.
  • Additional parts are required to facilitate this transmission conversion.
OEM Application List
2005-2008 Pontiac Grand Prix GXP 5.3L V8
2006-2007 Chevrolet Monte Carlo SS 5.3L V8
2006-2009 Chevrolet Impala SS 5.3L V8
2008-2009 Buick Lacrosse Super 5.3L V8
Swap Application List
1997-2014 W-Body with LS4 V8 Aluminum Subframe


Watch the video below to learn more:

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