Well here is how funny Our Motors can act when it comes to Low Octane. I was pushing better then 13-1 compression Motor far from stock. Reach in Bump the key she'd fire right up (to may surprize It started on the pump stuff 87) Never a Ping one Or any Marks in the pistons due to Not enough Octane. But Never try to shut this Beast OFF because it wasn't going to happen. I Used to load the clutch to shut it down. First Time I had Blowen the head gasket I was exspecting to See All Kinda Marks in the top of the pistons. NOT One to be found. And you never heard this thing Ping either. But Yes It could be a Issue with the Stock cam. But If you have a dished piston You shouldn't have any issue The 10-1 with the flat top and stock cam Maybe??