360 mystery breakdown

The thing that's strange is I actually thought I had the timing nailed down; after I cut a hole in my hood and attached a scoop I can't remember hearing it ping much at all really. I had also backed the timing down a hair and even richened up the carb a tad when the weather started getting cold.

When the head gasket blew it was pretty cold outside (15*F) and I was going down the highway at 3000 RPM just under 80 MPH; I stepped on the gas and got into the secondaries for a bit of "fun" and to pass a line of cars going super slow, once I let off I realized something wasn't right and once I pulled off the road and popped a valve cover it was obvious (inside of valve cover was coated in what looked like vanilla milkshake). Like I said I hadn't heard any AUDIBLE pinging for a long time but I know that doesn't mean it wasn't happening.

AJ I have talked to you before a couple times about my engine (been a bit though), it's a 1975 360 LA block with factory crank and rods, KB 107s, and factory iron Magnum heads. When I built the engine I cc'd the heads and calculated the true static compression to be 10.42:1. The cam I used that I think was way too small was the Lunati Voodoo 256/262 adv. duration (213/220* @ .050"), especially with the 1.6 Magnum rockers I think the cylinder fill was just too much at too low of RPMs. Peak torque on this thing felt like it was 2800-3000 RPM and it liked to be shifted barely past 5000 RPM.