The detonation is really a function of camshaft centerline in these cars. You need a wide centerline on a big Pontiac to avoid detonation and get the most power. That was the nightmare of the engine in my black '72 455HO. Back in the 1970's an "expert" engine builder slapped in some domed pistons (which Pontiacs don't take kindly to) and a crappy cam choice. The thing would detonate under any load, even with the timing backed off 20 degrees! It had around 11.5 to 1 compression. When I did a compression check it showed 225 PSI!!!
A lot of guys swear by the Summit Racing 2802 cam (if they are not going the rollercam route). And you can't beat the price! That is what is going into this motor. - The Melling SPC7 reproduction RAIII/455HO 068 cam I had just installed in the 350 is too mild for the 455 with these heads. So I guess I'll save that for the next project.
http://www.summitracing.com/parts/sum-2802
There are some very informative discussions on cams on the PY site by some of the better engine builders. Here's one:
http://forums.maxperformanceinc.com/...d.php?t=775018