It's right hand. When I did my Renntech install, my dealer let me use their flywheel locking tool. It's a gear segment with 2 pins. After dropping the exhaust and the starter, the pins go in where the starter bolts were as the gear segment engages the flywheel ring gear. There is then NO movement when breaking loose the bolt.

It took a 5 ft long pipe (floor jack handle actually) on my 1/2" drive breaker bar to break the bolt loose. I installed with a new bolt because the service manual specifies a maximum "stretch" length to discard the bolt at, which makes sense because of the torque required to tighten. It took the 5 ft pipe on the breaker bar to again tighten the bolt to the correct spec. I can't imagine getting the bolt loose with an impact. I jacked up my compressor to over 150 psi, and only my 1/2" drive impact fit in the space. It wouldn't budge the bolt. Thus the locking tool and 5 ft pipe.