Magnum cooling
Won’t it ping with 40-50 degrees of timing at cruise? That seems like alot?
Not with that little load on it. It’s close to the same as NA in this case.
The cylinder isn’t packed tight with fuel and air. The molecules are a long way apart compared to full boost or full throttle NA.
So it takes longer to get the burn complete.
With the timing retarded like you have it, the burn still gets completed but it’s so late that it’s finishing in the pier and out into the exhaust.
That slow, lazy burn generates an incredible amount of heat late in the cycle.
It drives coolant temperatures through the roof.
Just like you are experiencing.
That’s why 99% of NA engines should be using vacuum advance. It’s the same thing.