G'day All, new here but wonder if I might find a few new ideas ...

I got a Merc 450 V8..'76 and first of the K Jets and pre pollution.

The problem is a vacuumn advance ping that I don't believe is because of the low octane Super we get nowadays.

Advanced curves are spec.

KJet is right where the engine likes it .

Have compared comp press' with same year engine that didn't ping.

Only thing I don't know is the profile of the crown of the pistons .

I wonder whether the ping is some swirl experiment that was easily sent into detonation..???

I think the engine might be a '75 engine ....the fuel head has a solenoid at the back thats refered to only as '75 models