Pinging Problems

[mikajo39]

Ok here's my dilemma my engine seems to ping pretty bad on the drivers side only(350) at part throttle, even with vacuum advance disconnected. It has 9.5-1 compression with iron heads. I have to back the timing off to where it doesn't ping for me to drive it and when its backed off that far the timing is too retarded and I get full throttle stumbles. It'll ping when cold too. I've tried different advance springs, when it runs good ( no stumbles) the timing is 34 deg all out at 3200 rpm but It will ping on the freeway. Should I try a colder plug? Or could my jetting be too lean and making it ping? I'm pretty frustrated with this blasted thing, it's new and I can't even have fun with it without problems.