Performance mixed with fuel economy!?

MopaR&D said
The rough-cast open chamber heads sure don't help either. The 360 in my truck is right around 8:1 with stock heads and it'll ping with more than about 34 degrees of total advance at WOT. Whereas my Duster's 360 is at 9:1 but has Edelbrock heads (the quasi-open-chamber ones but aluminum and with much better surface finish), max power timing is 40 degrees (confirmed on a chassis dyno) and I've never once heard it ping.

After years of screwing with this stuff, I can say unequivocally that the surface finish of the combustion chamber has zero effect on detonation or detonation resistance. In fact, I can (and do) suggest that you polish the chambers to get them to equal size and then use a burr finish on them.