If your hearing is better than mine and you can actually hear a detonation rattle, retarding the timing a few degrees might be in order. I stopped hearing faint rattles years ago, so I have to use one of my grandkids on a test drive to tell me if an engine is detonating. Definitely DO NOT advance the timing for load-pulling- - - -you'll burn big holes in the pistons!
On more dyno runs than I can remember, we found that once the maximum torque "sweet spot" for timing is found, advancing even one more degree robs as much power as a 5 degree retard from that point. Always err on the side of "not enough" timing advance- - - -going too far the other way tries to run the engine backwards and destroys some very e$$pensive parts!!
Jerry
