Another "recommend a cylinder head?" thread!

It was built by a reputable engine builder (my good friend Norm Sappenfield, "mechanic to the stars" and well-known builder of land speed record engines), always ran well and still does except for the detonation.

For those who are interested, here's a thread on another forum showing Norm and one of his satisfied customers:
OT gotta boast - rebuilt flathead ... - Yesterday's Tractors

When he built it, I told Norm that I wanted to take the car to the drags, but then life intervened so I never did. (I would still like to get some time slips with this car some day.) It pings really badly at almost all throttle openings, even when not accelerating, and even when the initial timing is reduced to 8 degrees or so. (Idles really terrible with the 8 degrees of initial.) It seems to like 18 degrees or so of static timing the best. So thanks a lot for helping me, and in order not to waste your time I am going to pull the heads and first make sure I haven't damaged the pistons or cylinders, and assuming I haven't, I'll CC the combustion chambers and make all the measurements you guys have asked for, and will get back to you. I'm not sure when that will be, though. Surely not until the weather warms up. So I'll be reviving this thread later for sure. Thanks again.