Why is it so hard to get good advice !!???

Rod-length on a 493" stroker is 'usually' the same as a stock 440-length. 6.7xx" thereabouts I recall.

I'm having a somewhat similar problem my own Eddy headed 493".
I went from a stockish hydraulic cam with 1.6 rockers, to a solid roller cam with 1.5 rockers. (1.5 rockers to stay below the .600 lift range of the springs).
The roller cam is the CompCams XR274R-10.

Now the engine pings after it gets warmed up (under the hood), mainly because that cam creates more cylinder pressure.
It doesn't ping when it cold so I'm fairly sure the pinging also has it's origin in the hot air being drawn into the motor.

Creating a cold air intake is something I would strongly advice looking into at first for your problem. Also try keeping the engine-temps low enough by using a 160 T-stat for instance.