Since I now work at a dealership I took some more measurments of the ZL1 hood insert.
And since I have a holden flat hood that was damaged in shipping. I made a paper template to lay over it to see how it would fit.
I then realised that the ZL1 insert would be too long to work, so it would need to be cut shorter in the back because of the hood latch area. So the hole for the vents could start around 10-1/2 to 11 inches back from the front lip of the hood.
So this would be the actual placement of the ZL1 insert on the Holden flat hood... Unless you decide to add the cowl section then you'll probably have some extra space to decide where you want it to rest. The square areas in black marker are where the vents will be.
Hopefully tomorrow (if I have time) I will lay the template on the G8 hood and post some pics of that.
On a side note I did ask the parts guy at work to price out the official GM Camaro ZL1 insert and he asked "black or carbon fiber?" I said "black." When he brought it up on the computer I thought the poor guys eye's were going to pop out of his skull. He said "GM want's around $2300 for it." I was in such shock I didn't even bother to ask what the carbon fiber version costs.