Causes of detonation?

ramcharger said
I'm thinking that you have not checked your distributors curve and have to run a lot of initial timing to get it to idle but that pushes your total timing way over what you really need. Tell us what your initial and timing total are.

Moper is right about oil causing problems too, whether it be from valve guides or ring wear.

BTW, did you use the recommended valve springs from Lunati for that cam? Were they checked when in installed for bind and proper installed height?

ramcharger nailed it on the head. Turns out the remanufactured electronic distributor has a very wide mechanical advance curve and is set up for engines running close to TDC initial timing (I guess for emissions). With my dial-back timing light and the initial set around 10* I ended up with almost 40* total around 3400 RPM. Put the initial back around 5* and the pinging is gone. After I get exhaust I think I'll have my distributor recurved by FBO.