With modern Mopar performance booming, Gen III Hemi cylinder heads are a hot commodity. Thitek Cylinder Heads’ new “Bear” cylinder heads are cast from A356 T6 aluminum and are designed to enhance the performance of both boosted and naturally-aspirated applications through a variety of features and options.
Starting on the intake side, the Bear heads will work with standard Gen III Hemi or Hellcat/Demon-specific intake manifolds, and the intake ports are completely CNC-machined. Then, the options start.
“There are two different exhaust ports available – one that uses a 1-7/8-inch header, and one that uses a 2.0-inch header,” says Craig Thibeau.
The dual exhaust bolt pattern makes the cylinder heads completely ambidextrous left to right, with the added benefit of the dual exhaust bolt pattern allowing turbo users to flip the exhaust manifolds for forward-mounted turbochargers.
“There are three different chambers available as well. There’s the taper-plunge chamber, a normal Apache-style chamber, and then a wide chamber that is more of a traditional Hemi style chamber, for specific applications and desired compression ratios,” Thibeau says.
All three options are CNC-machined and feature ductile iron valve seats with bronze valve guides, as standard, while retaining the stock dual-plug layout. In addition to the three chamber sizes and designs, there are four different size intake valve options on the complete heads, ranging from 2.080-inch valve that flows 370-plus CFM on the small end, to a 2.200-inch valve that flows more than 410 CFM.
The rocker arm stands have been reinforced over the stock design, as well, which not only strengthens the rocker system mounting, but also adds rigidity and helps reduce deflection. The complete heads are also available with either PSI 1511 beehive valvesprings or optional PSI 1512 dual valvesprings to work with the factory rocker arm system.
Cast in Ohio, and machined in Michigan, the Thitek Bear heads are made entirely in the USA and are also offered in a porter’s version with small, unfinished chambers and ports, with no valve seats or guides installed. These things are seriously badass: X275 racer Rob Goss has used them atop his record-setting Challenger to run some seriously-quick times in 2017. If you’re serious about Hemi performance, you owe it to yourself to take a look at these.