My '12 doesn't have any telltale bolts that are apparent between the pulley and external balancer...at least I'm assuming it's an external balancer like my Chevy's had...just a central bolt that appears to hold the whole assembly on to the front of the crank. I can't tell if there's a split between the pulley and balancer, but I guess they could be keyed in some way. Maybe a parts fiche or pic at the parts counter would show that?...or is there an online parts diagram? I don't see anything on the March site to show any late model hemi options. I haven't had one of the later 4.8/5.3 Chevy's and didn't realize they'd started making them as one-piece assembly.