This project has been about 10 months in the making. Sinister Performance started this project last year with a ProCharger, a custom ground Inertia Motorsports cam, long tube headers and a cat back exhaust. this combo made about 505RWHP which the customer was very happy with. Soon after he decided he wanted to make the engine stronger by putting in a forged rotating assembly. Sinister Performance decided that if the engine was going to be removed and rebuilt, they might as well make it a stroker motor.

Sinister Performance decided to go out of the box a little on this build. Rather than buy a complete stroker kit, they opted for a Callies Forged Crankshaft and Rods, and Diamond Forged Pistons. The weak point in any Hemi engine are the pistons. Due to the height of the upper ring land, the top of the piston is very thin. With the custom 9.0:1 pistons they ordered from Diamond, they were able to lower that ring land and essentially make the top of the piston thicker. Sinister Performance port matched the heads to the 6.1L Intake manifold and radius cut the valves, installed ARP head studs, an ATI Dampener SFI rated and with an 18% overdrive to minimize belt slipping on the supercharger. They also installed an Arrington 90mm Throttle body. Sinister Performance upgraded the fuel system with a bigger Aeromotive fuel pump and Cobra 54lb Injectors.

FLI made an engine break in map and after 1000 miles, the final custom tune was performed. During the baseline dyno run (FLI custom tune with stock engine and Procharger kit, 7 psi of max boost) the dyno room temp was 65 degrees with 33%. humidity.  The latest custom FLI tune, max boost was 7.5 psi and the dyno room temp was 75 degrees with 34% humidity.

This Challenger made very impressive power gains from this custom engine package.  There is a lot more room to grow, but for now the customer is very happy.  For more info about this build, visit Sinister Performance’s blog here.