Besides the extra cyl pressure, many say that they produce a ticking of pinging sound because they slap the valves shut so hard.
The Voodoo cams are said to have a similar steep opening ramp, but close the valves more gently, thus not making the ticking sound. Pontiac engine builder Paul Carter also says that, in his experience, the Voodoo cams do not promote detonation like the XE cams do.
Most say that cams with more adv duration will "bleed off" some of the cyl pressure, reducing the chance of detonation.
So, something like an 068, might solve your pinging problem. For a little more performance, the Summit 2801 is sort of a high lift version of the 068. So, it should make more power. I like the looks of it for a mild street 400.
And, the 262 Voodoo should reduce pinging, and increase performance, since you should be able to increase your total timing. The low timing is said to promote overheating.
