ZR51 Performance - 6-speed Manual Transmission Specialists 

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LS1 ZF6 C4 Corvette - A Different Approach

Ever since the LSx motor was conceived, I oftentimes wondered what it would be like to drive an LSx motor coupled with a ZF S6-40 6-speed transmission. 

Congradulations to jsdnfkasjdfjkasd for being the first to create a C4 LSx with ZF 6-speed package.


 . The T56 is a great transmission given its dated synchronizer design technology. The Y/Body T56 platform received several proprietary design upgrades and recently evolved into the newly designed T6060  transmission.. The T6060 synchronizer assembly design is more advanced than all previous T56 models, now incorporating technology nearly the same as that of the ZF S6-40 transmission platform, introduced 20 years ago. 



  provide better balance/shift performance. The T6060 synchronizer design incorporates now    design and is more similar to teh 21 year old  because it has rolled in . T I've driven lots of  LSSince August of last year, 200 hours of R&D has brought this  

The LSx Gen III engine provides amazing performance at an affordable price. Until For years I have wondered how the combination of   

Vehicle History:  I am the original owner of this 1989 Z51 6-speed Corvette Coupe. In 1992 the body was professionally converted over to a wide-body (ZR-1) configuration. I repainted the vehicle last year with a kandy-apple red over solar-gold base coat. After 234,400 miles, the L98 engine in my ‘89 C4 was put down. That L98 served me well…RIP.

Clutch: The F/Body T56 bell housing ($150) was purchased from a private sale. The stock LS1 clutch kit ($400) with stock F/Body LS1 Clutch Hydraulic Actuator ($85) and Extended Bleeder ($95) from Tom at Carolina Clutch 888.462.2739.

Clutch Hydraulics: The C4 master cylinder will drive the F/Body LS1 slave cylinder enough to achieve the required 0.350” to 0.475 “ of travel required for the LS1 stock clutch to completely disengage.


Engine Cradle and Mounts: For our application, we chose to update the engine cradle and mounts to the newer ’92-’96 C4 configuration which after structurally modified provides ample clearance for the LS1 A/C compressor plus enough clearance to service the A/C serpentine belt. Unfortunately engine removal will be required when replacing the A/C compressor. Our hot summers here in Phoenix Arizona make A/C an absolute must have requirement.


C4 LS-ZF6 Adapter Plate:   The 1.317” thick adapter plate front face emulates the mating surface and actuator mount of a ’98-‘01 LS1 F/Body T56 transmission front adapter housing. The adapter plate rear face emulates the rear face of a ZF S6-40 bell housing. The CHS Actuator bolts up to the front face of the adapter plate in the same manner it would bolt up to the front of a T56 transmission. The adapter plate with affixed throw-out bearing is then fastened to the T56 bell housing. The ZF S6-40 transmission must be equipped with a longer 190.5 mm (7.5”) ZR-1 input shaft which by the way is the same length as the LS1 T56 input shaft. The ZF guide tube is cut down to 0.250” height providing clearance of the input shaft for insertion through the adapter plate retainer ring hole and CHS actuator which replaces the ZF guide tube. This clutch configuration guarantees successful operation due to the fact that it is identical to the ’98-’01 F/Body clutch and housing configuration. With this configuration, the input shaft pilot tip has full contact with the pilot bearing needle rollers as well as the required 0.100” to 0.200” of tip-shoulder clearance.

More information and picture to follow.

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Send email to billb@zfdoc.com or call Bill Boudreau at (602) 319-6575.
Last modified: September 22, 2009