In an effort to capitalize on the phenomenal performance potential of GM's LS engine family, the aftermarket has released a bevy of cylinder-head castings to cover everything from 3.90-inch (LS1) bore sizes through 455ci strokers featuring up to 4.125-inch bores. You can now add one more player to that list, as Bill Mitchell Racing Products (aka World Products) has finally released its long-awaited Warhawk LS1X aluminum heads.

According to Charlie Amodeo of World Products, "The LS1X head is a clean-sheet design that features factory 15-degree valve angles and is primarily targeted at [customers] looking for excellent power potential at reasonable prices. The heads flow over 300 cfm on the intake and are built with lots of extra material to allow additional porting and airflow gains."

"The heads [in this story] were actually pre-production units sent to us for evaluation and product testing," says Pete Incaudo of VMax Motorsports. "Through a long-standing affiliation with Bill Mitchell and World, we worked toward the goal of getting them very close to what would ultimately be offered by World in the retail market. Since I have performed numerous cylinder-head evaluation tests for GM-including pre-production LS1 castings in 1996-it was a great opportunity to evaluate the World design and provide feedback. In addition to testing the heads on a flowbench, we wanted to see how much power could be generated on the dyno."

Follow along as we install a set of the new LS1X heads on an '02 Z06 owned by Kevin Turner of Carrollton, Texas. Other than a Halltech C5 Venom air-induction system, the car was bone stock prior to our ministrations. To help us extract maximum power from the combo, VMax and Real Performance Motorsports (RPM) spec'd out a nasty combination featuring Kooks headers, a rowdy Comp bumpstick, and a FAST intake manifold with a ported 90mm LS2 throttle body. Installation was performed at RPM HQ in Lewisville, Texas, by technicians Manuel Bejar and shop manager Keith Lohse. Company co-owner Brian Lohse, meanwhile, tuned the combination with HP Tuners' VCM Suite software.