Heli-coil will work just fine. There isn't much stress on the valve cover bolts. Put the coil in with your new bolt and grommet and you should be good to go.
Predator owner since 2003
2009 Polaris Outlaw 525S...in-work building.
2005 Pedator
Twin Air clamp-on, Edelbrock, Rath A-arms, Dyna FS, Rath Rear Hubs, PEP Shocks (built by Rath), Flexx bars, Hiper Wheels, Razr 2 Tires, P&P cylinder head (Nicholas Cycle), Rath Head Pipe, Pro Armor Kill Switch, Yoshimura slip-on, Pro Armor nerfs, JE 12.5:1 Piston, Trail Tech Dash and Endurance Computer, Home made radiator scoops and chassis skid, PRM Bumper and Grab Bar.