Looking for upwards of 700-plus horsepower in entry level trim and more than 900 ponies if mild boost is ordered, the engine will be based around a Bill Mitchell aluminum block and the very imposing Arias LS hemi cylinder heads. The first test market for this eye-catching design will be high-end sand rails where owners invest just as much in paint and graphics as they do in performance.
“This engine definitely lends itself to aesthetics,” confirms TCB boss Robert Bentley, noting the massive valve covers and bold intake manifold designs that are available.
Grabbing attention isn’t the only goal of this engine project. TCB is evaluating and testing a number of cylinder modifications to ensure an off-road-friendly torque curve to go along with peak power numbers.
“This head was designed for drag racing,” says Bentley. “We’re not looking to redesign the head. We’re looking for different effects with a little modification for different applications.”
TCB engineers have been filling the intake ports with epoxy and reshaping the airflow for a wider range of efficiency. A full range of flow tests on a SuperFlow bench are then conducted and the results analyzed.
“We can then map the port and duplicate it on the CNC machine,” adds Bentley.
No cookie-cutter engine builds
TCB, a full-service engine shop located in Murrieta, California, already has a strong reputation in the street rod and boat-racing markets. The move into off-road isn’t completely unfamiliar territory new as the shop has built 900-horsepower Trophy Truck engines for desert racers.
“We’ll be leveraging some of that technology for this engine,” says TCB marketing director Jack Rothschild.
TCB will work with a variety of suppliers to round out the build sheet.
“Every design will be built to the budget and needs of the customer,” says Bentley, adding that displacement will range from 440 to 480 cubic inches, depending on the vehicle application and customer wishes.
The hemi cylinder head allows for huge 2.260 intake and 1.600 exhaust valves on a 4.125-inch bore. Out of the box they’re rated at 380 cfm intake and 268 cfm exhaust. With a full port and polish the heads can flow over 400 cfm on the intake side and 300 cfm on the exhaust. They require shaft-style rocker arms.
“We’ll develop the cam profile to fit the heads and motor,” says Bentley, adding that the engine should run 6,800 to 7,200 rpm with strong torque numbers coming in around 3,000 rpm.
The first development engines will be carbureted using the Arias cast intake manifold, which has provisions for single or dual carb top plates. It’s also predrilled for nitrous nozzles but there’s limited real estate for fuel-injector bungs. EFI may require a fabricated intake, a Hilborn-style injection setup, or there’s always the option of throttle-body fuel injection in either single or dual configuration. Arias also has an intake to support an 8-71 Jimmy-style blower.
TCB will also be developing Arias hemi heads designed for the big-block Chevy and small-block Ford. EngineLabs has a closer look at these heads in this story from PRI. We’ll keep you posted when the first off-road LS hits the dyno.