PRI 2011:The Driveshaft Shop and Hammerhead build Modern IRS 12 Bolt

12 bolt IRS Hammerhead Benefits and features:

  • Contains 1400HP capable 30-spline axles
  • Less horsepower loss than a 9″ Ford
  • Large access to gear ratios, posi-units, and even racing spools
  • Cast aluminum, and available in nodular iron for extreme use
Having an engine that produces massive amounts of horsepower is always a good thing… Right? Well of course it is, but that amount of horsepower really can wreak havoc on a driveline. That horsepower will find the weak part of your system, and more often then not, it ends up being the rear differential of the vehicle.

This is what led The Driveshaft Shop and Hammerhead housings to partner together and build the Hammerhead, a 12 bolt independent rear suspension(IRS) for late model vehicles. “We’ve partnered together with skip lee from Hammerhead development, and he came up with a casting on a IRS that basically holds a 12 bolt center section for the modern muscle cars.” Explained owner of the Driveshaft Shop Frank Rehak.

“Frank and I have decided to offer this as a complete kit, for one stop shopping,” Hammerhead Housings Skip lee told us. “It would be a one day installation with any shop with a hoist.”

The Chevy Camaro Hammerhead IRS which they had on display at the show, will come available in three stages:

Bulletproof stage 1

  • 33 spline Eaton TrueTrac for normally aspirated cars. 3.42, 3.55, 3.73, 3.90, 4.10, 4.30, 4.56, and 4.88 ratios.

Bulletproof stage 2

  • Optional 35 spline WaveTrac with lifetime warranty for supercharged and manual transmission applications.
  • Indestructible nodular iron casting also available for applications over 1000HP

Indestructible Stage 3

  • Optional solid spool and 9310 alloy “Pro Gears” for racecars only, 4.11, 4.33, 4.56, 4.75, 4.88, and 5.00 ratios.


The Driveshaft Shop also showed us their new carbon fiber driveshaft that weighs less than 15 pounds. “We’ve perform extensive testing on not just our carbon fiber driveshafts but on every one we offer. Explained Frank. “We test our driveshafts on our 9500RPM Speed Balancer to be able to not only bring the Carbon shafts into production, but also make sure they are the best balanced and manufactured shafts available.”

For more information on the complete line of products available at the driveshaft shop visit their home on the web at


About the author

John Gibson

John has been around dirt track racing his entire life. In fact, he was almost born at Monett Speedway in Monett, Missouri. He has raced everything on dirt and asphalt from karts, to Indy cars, to 650 horsepower stock cars in the USAR Pro Cup where he currently races.
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