C5 guy here. My father has a 2005 LS2 and the balancer bolt started walking out. Car has 80k on it and we are going to just replace the balancer with an ATI and ARP bolt. I was wondering if the LS2's were keyway from the factory. I know the C5's are not. If the C6 isn't I might as well also get the ATI crank pinning kit to basically correct GM's stupidity. Thanks. BTW a search yielded nothing useful so please just post the answer.

 

Nope.
Plan on pinning the crank yourself.

 

I installed ATI balancer on mine. it comes with single keyway in balancer but you may be able to order with double keyway. I cut second keyway in mine and double pinned with ATI pinning kit. Kit may cause cursing but after some modification will have great result. either reaming bit or drill bit was to short to use in car.fixed by welding length of push rod to bit. inside i.d of push rod fit o.s i.d of bit. approx. 6 1/2 inch long will work fine. knurled fixtures that you will drill and ream thru slightly too large in diameter. you will need to grind down so fixture dosent bind against front engine cover after drilling to switch fixtures. if not ground down you will have to back off crank bolt to release pinning fixture and lose your hole indexing. guess how difficult to find hole if you do that? as the knurled fixture rotates against the front cover at end of its rotation leave enough material in this area so fixture can lock against engine cover to stop it from spinning when drilling and reaming. without doing this I could not get fixtures to release to change.bound solid!hopefully may help someone. in and out slowly once only with reaming bit! 8 rib balancer may be used in this application with your 6 rib serpentine belt if any chance of supercharging in future you will be good to go and dosent cost anymore. Dan